Coming off his landslide victory in Nevada, Donald Trump is unquestionably the strong frontrunner for the GOP nomination. He's the national poll leader as well as the poll leader in the overwhelming majority of states between now and March 15. He's got the most dedicated supporters. Unless something significant changes in the dynamics of the GOP race, he's going to be the nominee.

Nonetheless: There are other Republican candidates who would resent the implication that such change is impossible — or that they could not be that catalyst for that change. And, indeed, it's still possible for Marco Rubio, Ted Cruz, or even John Kasich to prevail.

On the eve of Super Tuesday, it's worth looking at just what they'd have to do, including navigating a brokered convention, to make that possibility a reality.

1. Marco Rubio's path

The main thing Marco Rubio needs to do is actually win. And, contrary to his own campaign's recent assertions, he can't wait until Florida on March 15 to do it.

First, he's hardly a lock to win Florida — he's polling 16-20 points behind Trump in the latest polls there, and that certainly won't improve if he loses every contest between now and then. Second, if he doesn't win any of those 20 states, somebody else will — and that somebody will rack up a massive lead in both delegates and popular support that Rubio will be unlikely to overcome.

Moreover, the territory after Florida is not actually great for Rubio.

He's not a strong candidate in the Midwest — certainly not compared to Trump. The first major Midwestern contest, in Michigan, actually comes before Florida — and Rubio is polling more than 20 points behind Trump, and barely ahead of Cruz and Kasich. Even if Cruz fades and Kasich never gets a second look, an aggressively internationalist movement conservative like Rubio is going to struggle to win states like Ohio, Illinois, and Pennsylvania against a populist champion of trade war with China and America-first foreign policy like Trump.

And Rubio's odds look even worse in the Northeast, Trump's home region. He polls at only a third to a half of Trump's support in Massachusetts, which votes on Tuesday. And while there are no recent polls from New York, Trump's home state, his endorsement by Governor Chris Christie of neighboring New Jersey and Trump's close relationship with former New York City Mayor Rudy Giuliani emphasize that this is one region where Trump not only has good polling numbers, but also good relations with important figures in the GOP.

To be fair, there have been no polls since the most recent debate, where both Rubio and Cruz attacked Trump more aggressively than they had before. And it's possible Rubio's recent attacks on Trump as a "con artist" will dent Trump's support, and help him close with late deciders, as he did in Iowa.

However he manages to do it, though, Rubio needs significant victories before the battles for the Midwest so that he has a fighting chance there — and so that he can be the strong favorite to win late-voting delegate-rich states on the Pacific coast, Trump's worst region. But where can he do it? And how?

Let's look at a few favorable Super Tuesday contests.

Minnesota: It's a prosperous state with a relatively conservative GOP and relatively low racial animus. Rubio almost got past Trump in nearby Iowa, and Cruz's star has faded considerably since then. And in the most recent poll of Minnesota voters, back in January, Rubio actually led the field — and Trump was third. Since then, Rubio has won the backing of the state's largest newspaper; he also has the support, for what it's worth, of two former senators and the former governor, Tim Pawlenty. If any Super Tuesday state is Rubio territory, this is it.

Georgia and Virginia: Virginia is also a prosperous state with a relatively conservative GOP — and if there's any state where the GOP establishment and movement conservative organs still have some weight, it ought to be Virginia. Georgia offers promise in the wealthy Atlanta suburbs and other prosperous parts of the state. If you squint hard, and pick only the most-favorable polls, Rubio looks like he might be in contention in Georgia, and to a lesser extent in Virginia. He's still got a lot of ground to cover — but there are few places in the South where he has a better shot to cover it.

Beyond those two key states are potential opportunities in Arkansas, Tennessee, and Oklahoma, border states that should be more favorable territory to Trump and Cruz, but where some polling has shown a close three-way race, and where, once again, Rubio has been picking up some high-profile endorsements (most recently of Governor Bill Haslam and Senator Lamar Alexander of Tennessee). All three states allocate delegates pseudo-proportionally, and all have relatively high thresholds for earning any delegates, so if Rubio can get above 20 percent he can at least minimize Trump and Cruz's delegate advantages.

Rubio's message

If you look at the above map, what you'll see is that Rubio's main challenge is to sideline Ted Cruz — not just squeak by him as he did in the last two contests. That means winning over Cruz voters. And that means changing his message.

More than any other candidate in the race, Rubio is running as the candidate of no change. Yeah, he's young, he's Hispanic — whatever. Yeah, he's got a lot of policy papers on a host of issues — that's nice, so did Rick Perry. The overall message is still: back to the future. Both in foreign and domestic policy, Rubio is running as if everything the Bush Administration wanted to do in 2002 was a brilliant idea, and all we need is to get back on that shining path to glory. That is not a winning pitch, not in the primaries and not in the general election.

I'm not sure whether Rubio is running this way because he really believes this stuff, or because he's afraid to take the risk of coloring outside the lines. I suspect it's a bit of both, and that they are mutually-reinforcing tendencies. Rubio is an ambitious young man — but ambitious young men need powerful patrons, and Rubio aims to please his. Plus he strikes me as somebody with a deep need to believe in something — which is not the same thing at all as having a strong character. Regardless of the reason, Rubio's preference is to run on some combination of "I'm such a nice young man" and "I'm the most electable candidate." These are not pitches that will peel voters away from Cruz — or Trump.

What he's added to the mix in recent weeks is an aggressive, sometimes sophomoric fusillade of attacks on Trump. Some of these should have real bite: Trump's business record is nowhere near as strong as he makes it out to be; there may well be skeletons hiding in his tax returns; and Trump richly deserves a taste of his own insult-dog medicine. But Rubio is singularly poorly-placed to make these attacks, not only because their deliberately juvenile style make an already-callow candidate look even more immature, but because Rubio himself is such a creature of marketing. When your main claim to the nomination is "I may not have much experience, but I look like somebody people can project their hopes and dreams onto," it's hard to get traction calling another guy a con artist. The risk is that voters understand "con artist" to mean "not an authentic conservative" — and that line of attack on Trump has been falling flat for a good long time.

What might have worked better would be for Rubio to take establishment support for granted, and burnish his anti-establishment credentials. He should trumpet the fact that Right to Rise ran all those ads against him — they prove he's not the establishment's real pick, but somebody they once tried to stop and now have to settle for. He should remind people that he defied the Florida GOP to run against Crist, and that he did so because he disagreed with Crist, not just because he saw an opening. He shouldn't offer the VP slot to John Kasich — he should say he'd hire Donald Trump to be our chief trade negotiator.

Most important, he should start acting like someone who's running to accomplish something, and something of his own, rather than somebody who really, really wants to be president, and who's trying to convince the voters that other people would like him to be president, so they should too.

I don't think Rubio has it in him — and it's too late to change gears for this round of contests anyhow. Then again, I've never liked Rubio, so maybe I'm unduly skeptical of his current strategy.

2. Ted Cruz's path

Ted Cruz has a much less plausible path to the nomination — but it's not yet impossible to see him winning. He's got the money and the organization to go the distance. He's polling competitively in a lot of states on Super Tuesday — more strongly than Rubio, in many cases. And, like Rubio, one can imagine him doing well out west — if he gets that far.

To get that far, Cruz has to derail the Trump express on Super Tuesday.

He has to win Texas — and win it decisively. That should go without saying — but even though he's been leading in his home state for some time, Trump is close enough that Cruz shouldn't assume it's in the bag.

He has to win the border states — Arkansas, Tennessee, and Oklahoma — where, as I noted above, the race is tight between Trump, Cruz, and Rubio. Throw in Rand Paul's Kentucky on March 5 for good measure. If he doesn't win any of these states, he probably won't win anywhere of consequence but Texas — and he's done.

There are a handful of contests out west — from Kansas to Alaska, with Wyoming and Idaho along the way — that don't have a lot of delegates, but that could help Cruz rack up wins. These highly conservative Western states are as good targets for him as exist on the map, and they are probably being ignored. Throw Minnesota into the mix, a Rubio must-win which Cruz could conceivably steal on the strength of organization.

Then there's Georgia, and the deep South states of Alabama, Mississippi, and Louisiana. I think it is going to be very hard for Cruz to take any of these states from Trump — and if he wounds Trump badly enough in Georgia, then Rubio might win there. Nonetheless, he has to fight for every vote in every one of these states — if for no other reason than to get above the threshold to receive delegates (generally 20 percent), and potentially to win a plurality in some districts (and thereby get two of the three district-based delegates in pseudo-proportional states).

Cruz's message

What does Cruz need to do to achieve the above? I'm not sure. Cruz's whole message is that he's a rock-solid, unwavering, and uncompromising conservative. So he can't really retool without destroying his brand. Moreover, these are very conservative states he's trying to win — if his brand can't win here, it can't win anywhere.

What he may have to do is sell the brand itself better. Cruz is very good at saying "I am the only one who is a true conservative." And he's good at saying, "If you nominate a true conservative, the great, dormant true conservative majority will propel us to victory," though his performance in South Carolina and Nevada has hardly lent credence to that theory.

But he isn't so good at saying, "America needs a constitutional conservative — because that's where the answers to our current problems lie." Nor is he so good at saying, "being a conservative isn't about checking boxes; it's about practicing fidelity, which is where you get the character you need to prevail in tough times."

If voters want someone who passes all the conservative litmus tests, he's the guy. But the overwhelming majority of voters — even conservative voters — don't want a guy like that. They want somebody who they believe can play a winning hand. And a lot of them — even very conservative voters — think that guy is Trump.

Can Cruz make that case that he's that guy, too? I doubt it. There's nothing in his record to point to, and his natural forte is as a debater, scoring clever points, rather than as a leader. But that, I think, is the case he needs to make to cut into Trump's lead across Super Tuesday — which is the only hope he has of surviving inevitable losses in states from Illinois to New York on the way to possible victories in North Carolina, Missouri, Arizona, and California.

The silver lining for Cruz is that, if he can win even a handful of states on Tuesday, and Rubio wins none, he can force the GOP leadership to reconsider their decision to coalesce around Rubio in the hopes of stopping Trump. Unfortunately, it's not at all clear that mainstream Republicans would consider uniting behind Cruz even if he were the only viable alternative to Trump. That's the main reason for Cruz to consider retooling his message, even now — so that he has some chance even if he manages to pull off a Super Tuesday upset.

It's a very thin hope — but that's where Ted Cruz abides.

3. John Kasich's path

In spite of being the most-qualified, most-presidential, and most-electable of the remaining candidates, Kasich has the least plausible path of all. But I would argue that all these paths are pretty questionable at this point, so his is worth examining.

For most of the campaign, Kasich has not been a factor in polling anywhere. He needs to change that — immediately. Kasich needs to demonstrate some evidence of national viability before March 15. Where might he do that?

New England: Kasich is way behind Donald Trump in Massachusetts and Vermont, and Maine (which votes on March 5) hasn't been polled (though Trump should get a boost there from Gov. Paul LePage's endorsement). If Kasich can outperform expectations in the region, and place at least a strong second, that'll at least give him a talking point going into the subsequent contests in the Midwest. An unlikely upset victory would certainly be a huge and positive surprise.

Virginia and Minnesota: As noted, these are states that Rubio absolutely has to win to demonstrate that he can win anywhere. If Kasich could snatch either or both, Rubio's candidacy could go into a tailspin — and Kasich would be in a position to pick up the pieces. Somewhat more plausibly, if Kasich at least polled above Rubio, that would be brutal enough for many of Rubio's supporters to reconsider their candidate. Unfortunately, Kasich is a very, very long shot even to come in second in either state.

Michigan: The good news for Kasich is that after Super Tuesday, most of the biggest prizes are in his strongest region: his native Midwest. Before Ohio or Illinois vote, Michigan gets its turn on March 8. Neither Rubio nor Cruz are well-suited to the state. Trump, on the other hand, is very well-suited. If Kasich has been out of the news for all of Super Tuesday, and especially if Rubio and Cruz have racked up wins, then I don't think he'll have enough oxygen to compete seriously here — and Trump will win. But if Kasich has kept hope alive on March 1, even without wins, and prepared the ground in Michigan, then he'll be in a position to capitalize on any good news that does come his way.

Michigan probably is must-win for Kasich, because the winner out of Michigan is going to have momentum going into Ohio, Illinois, and Florida — and if that winner is Trump, then Kasich probably won't win his home state on March 15, and his campaign will end there.

The Kasich path to the nomination really does depend on everything breaking his way. If Rubio does well on Super Tuesday, then Kasich won't get a second look — so he needs Rubio to flop. But if Trump dominates on Super Tuesday, then he's probably got the nomination sewn up. And since Kasich doesn't have a prayer of stopping Trump in the South, he needs Cruz to overperform, while Kasich himself overperforms wherever he has a plausible shot. Then, in a three-way race between Trump, Cruz, and Kasich... yeah.

Kasich's message

So: Is there any kind of message that delivers that outcome? That wounds both Rubio and Trump but also builds up Kasich?

I actually like Kasich well enough — certainly better than his competition — so I wish I could think of a way he could actually win. My best idea really is a Hail Mary — but then, so is his entire candidacy. Kasich should say whatever the heck he actually believes.

Kasich took ObamaCare's Medicaid money when the other Republican governors refused it. He should defend that decision without apology — heck, he should bring it up in his stump speech.

Does Kasich agree with Rubio's full-spectrum belligerence on foreign policy? From his record and from what he's said in the campaign, it doesn't look like it. If not, then he should say so — loud and clear, as part of his case for himself.

I expect Kasich believes Trump is a snake-oil salesman. So why is Rubio the one calling Trump a con artist? I wouldn't descend to talking about who sweats more or puts on more makeup, but an attack on Trump's experience would sound a lot stronger coming from someone with actual accomplishments.

Would it be enough? Probably not. But it would at least give him something to say. More often lately, he says stuff like this. I'm glad he doesn't think fulfilling his purpose on earth depends on being elected president — it's modestly encouraging to know he's not a maniac. But it would be good to know what purpose he thinks he's fulfilling by running.

4. The brokered convention path

Increasingly, the various campaigns — Rubio's in particular — have been talking as if their strategy doesn't depend on actually winning. By racking up enough delegates to deny Trump a majority, they can force the convention to go to a second ballot — and on that second ballot they can win.

I hate to break it to them, but this is not going to happen, for several reasons.

First, denying Trump a majority of delegates requires denying him a plurality in key states. But different candidates are in the best position to do this in different states. Rubio is not going to win Texas — only Cruz can beat Trump there. Kasich is not going to win Florida — only Rubio can beat Trump there. And Rubio is not going to win Ohio — not unless he's dramatically overperformed in contests before March 15 — only Kasich can beat Trump there. So a strategy of victory-denial requires a thoroughly unrealistic level of coordination among opposed candidates, whereby Cruz outperforms where he is strongest, Rubio outperforms where he is strongest, and Kasich also outperforms where he is strongest.

Second, many key states voting Tuesday don't really allocate their delegates proportionally. Instead, the at-large delegates are allocated proportionally, while within each district the winner gets two delegates and the second-place finisher gets one. What that means is that if, say, Donald Trump wins Georgia with 35 percent of the vote, while Cruz and Rubio both score in the 20s, and Trump's victory is pretty evenly spread across the state — a result similar to neighboring South Carolina, in other words — Trump could win upwards of 40 percent of the at-large delegates and two-thirds of the district delegates. That would be an absolute majority of delegates for the state.

Roughly the same system obtains in Arkansas, Oklahoma, and Tennessee — which, along with Georgia, are some of the best prospects for a true three-way race in the South. If Trump wins these states by a healthy margin, even with a plurality under 40 percent, he could well win a majority of delegates — and his competitors could be competing for scraps. Which would make the job of denying him a majority after the remaining contests that much harder.

Then there's the problem of "getting to eight." Anyone speculating on the possibility of convention fight really should read Donald Devine's exceptional piece on how the rules make that prospect extremely unlikely. In particular, note that only a candidate who wins a majority of the delegates from eight different states can be placed in nomination. Moreover, according to Virginia National Committeeman and rule expert Morton Blackwell, whom Devine quotes, delegates pledged to candidates who cannot be placed in nomination may not even qualify to vote on the first ballot.

If that interpretation of the rules prevails, that means that the threshold for winning the nomination may not be a majority of delegates, but a majority of delegates who are permitted to vote. And if Trump has a strong plurality of delegates, he is overwhelmingly likely to have a majority of delegates pledged to candidates whose names can be placed in nomination.

Consider: What are the odds that Kasich wins an outright majority of delegates from eight states, even if he wins Ohio? If he doesn't, and his delegates can't vote, then they can't be used to deny Trump a majority. Cruz has a somewhat better shot at qualifying — he should win Texas, and could pick up a variety of small, conservative states like Alaska and Wyoming that could ultimately add up to eight — but remember: He has to win outright majorities, and many of these states allocate their delegates proportionally. And if Cruz does qualify, then how much less-likely is it that Rubio makes the cut?

And even Rubio will have a hard time getting to eight — because there are only sixteen winner-take-all states. Trump has already won one of them (South Carolina). You've got to assume he'd be favored in states like Arizona, where immigration looms so large as an issue, and New Jersey, where Trump is well-known and where he just won the endorsement of the sitting governor. For Rubio to get eight majority-delegate wins while playing for second nationally would require outperforming in just the right places at just the right time, over and over again.

Finally: Regardless of the rules, if Trump comes in with the plurality of delegates, it is vanishingly unlikely that a brokered convention would produce a nominee unacceptable to Donald Trump, and vanishingly unlikely that it would produce a nominee from among the candidates whom Trump fought to the convention and defeated. It would be a transparent flouting of the will of the primary electorate, and an open invitation to split the party outright. If Trump comes to Cleveland with 40 percent of the delegates, and Rubio comes with 30 percent, the GOP would have to be out of its mind to nominate Rubio on any ballot. To have a chance at being the nominee, it's not enough for any candidate to deny Trump a majority. They'd have to at least garner a plurality for themselves. Which means actually beating Trump, and beating him repeatedly.

The bottom line

I've just spent a very long time explaining how each candidate can survive the map of upcoming primary contests, and amass enough delegates to have a chance of emerging as the nominee in the unlikely event of a contested convention. Now throw that column away. The map doesn't matter. Trump is running a national campaign, and he's winning everywhere. His opponents need to do the same if they want to have a chance at the nomination.

Anybody who wants to beat Trump knows by now that they can't just wait for him to lose or for somebody else to beat him. But there's still the delusion that somebody could win by consolidating the supposed majority of GOP voters who oppose Trump.

Nobody is going to beat Trump by consolidating the anti-Trump vote. There is no anti-Trump vote — or if there is one, it's nowhere near a majority. But there's an anti-establishment vote, a big one, which Trump has been rapidly consolidating.

Trump is not winning because he's a magician, or because America has gone crazy. He's winning, first and foremost, because he is the only one in the race who is defining the role he intends to play, while the others are all auditioning for a role defined by somebody else.

To beat Trump, a candidate will have to do three things:

1. Speak to the sentiment that has powered Trump's rise. That sentiment is anger and disgust at the detachment of the political system from the concerns of ordinary Americans, and even from reality itself. If you can't speak to that, directly, clearly, and honestly, then you probably don't have a winning argument this political season.

2. Make a real dent in Trump's persona. If you can't think of an argument why Trump would make a lousy president — or, worse, if you are afraid to make any such argument because you are convinced that Trump's voters will get mad at you for attacking their hero — then you are in no position to make any kind of claim on voter affection yourself. If nobody takes on Trump directly, and keeps taking him on, then Trump will win. Rubio and Cruz have finally started to do this, but it's very late in the game.

3. And, most important, make a strong case for yourself as the right person to lead America for the next four years. Not as the most electable, not as the one who other people think is the best candidate, and not as the one who passed the right litmus tests laid down by self-appointed guardians of the true flame. The case for yourself. As leader. Of America.

That doesn't sound so hard. Does it?