The GOP should be panicked.

We were told for years that in the 2016 presidential election, the Republican Party would boast its deepest bench in generations. A strong and growing core of accomplished governors and free-thinking Republican senators was going to revive the party for a post-Obama America. The GOP would rise again.

So much for all that.

Scott Walker was vanquished in weeks. Rick Perry, too. Chris Christie and Bobby Jindal are all but forgotten. Jeb Bush has won a pile of money and very little voter support to go with it. So now, Marco Rubio is being prematurely crowned the nominee in waiting. But it's the non-pols — Donald Trump and Ben Carson — who own the support of a full half of GOP voters in the actual polls. The GOP's best and brightest are getting stomped by a carnival barker whose vocabulary barely extends beyond "terrific" and "terrible," and an exceptional neurosurgeon who is completely incapable of being president.

We are fast approaching the nightmare scenario for the Republican Party.

It looks something like this: Over the next few months, Trump and Carson only drop a little from their polling highs. Ted Cruz's strategy of never attacking Trump's or Carson's supporters is adopted by the other actual politicians in the race. The continuing success of Trump and Carson means there will likely be only one spot for a traditional Republican candidate in the end. That causes the skirmishes between Cruz, Rubio, and Bush to intensify.

The reasons Republican money men are puckering up in fear, the reasons Mitt Romney's friends are talking up their man again, are plain to see. Cruz, Rubio, and Bush each have serious, potentially fatal flaws. If Trump and Carson hang on, non-populist Republicans will just have to take whichever establishment man is left standing. And that's terrifying.

Bush has proven himself to be an awful campaigner. He also has that last-name problem, where he takes away the "change" card from his own party running against another Clinton. As Trump pointed out, Bush also has a personality problem. Because Bush is already so clearly struggling, his rivals haven't even bothered going after him on immigration or Common Core, where the energy of the right can be energized against him. It really does seem like Rubio is going to whip him.

But that's a problem as well. Rubio has only run in one important election before this one: the Florida Senate race of 2010. He's green. His tax plan doesn't add up, even if it is among the best on offer. He's the best talker, but that's partly because he's just sticking to his talking points.

And then there's Rubio's immigration problem, which Byron York explored in his deep dive into the Gang of Eight bill. This is the domestic policy initiative that has the most Rubio fingerprints on it. Just 7 percent of Republicans support increasing the level of immigration into the United States. Rubio was the conservative Republican champion of a bill that would have increased the level of immigration. (He has since renounced some of this, but it's very murky.)

The immigration issue is changing the fate of political parties across the Western world. And young and fresh as he is, on immigration, Rubio is the candidate of the recent past. Someone else is the future.

That someone might be Ted Cruz. Now, Cruz's immigration attack on Rubio has been met forcefully by the Rubio campaign so far. But Cruz can rely on talk-radio stalwarts like Laura Ingraham, Michael Savage, and others to hammer Rubio on the issue constantly. This is bad for party mandarins. Cruz is loathed by his colleagues in the Senate. His persona electrifies his supporters and his detractors. To the establishment, Cruz looks like Barry Goldwater 2.0 — an uncontrollable right-winger, destined to be blown out.

So you see the near future playing out in the stress nightmares of the Republican establishment. Rubio eliminates Bush on age, polish, and the value of a last name. Cruz eliminates Rubio based on the Florida senator's support of amnesty. And suddenly, the deepest field in recent history has collapsed into Trump, Carson, Cruz, and some also-rans.

The GOP may get lucky. The race they want, where plausible candidates test each other over several primary contests, across several regions of the nation, may come to pass. Carson and Trump may self-destruct or annihilate each other. But, until something like that happens, leading GOP minds will live in fear of a Trump vs. Cruz battle. And they are right to fear it.