There was a time not too long ago in American politics when in order to win a party's nomination for pretty much any office, you had to be approved by the party's powerbrokers. Gathered in smoke-filled rooms, they'd decide which connected guy should be on the ballot, filtering out those who hadn't paid their dues or might embarrass the party come election day.

These days, any idiot can run. And given the right circumstances, they might just win. You can probably think of one important example.

So as Democrats hope to ride a wave election back into power in Washington, they may be asking themselves: Should we be rooting for Republicans to nominate the craziest, most extreme candidates they can? Or would that pose too great a risk if one of them should win? Let's examine the issue, taking the example of Joe Arpaio, who is now running for Senate in Arizona to fill the seat of the retiring Jeff Flake.

Arpaio, you'll remember, is not residing behind bars because President Trump pardoned him for a crime he had been convicted of, involving defying a court order on racial profiling. But that was just about the least-bad thing Arpaio did in his years as Maricopa County sheriff; if you like there's a good roundup here of his reign of terror, which included copious racial discrimination, horrific mistreatment of prisoners (an estimated 160 of whom died in his jails), targeting his political enemies for harassment, and in one bizarre case, staging a fake assassination attempt and framing an innocent man for the fictional crime.

As popular as Arpaio might be on Fox News, it's fair to say that the Republican Party would rather he not be their nominee. But from the Democrats' perspective, there are two ways to look at the race. On one hand, Arpaio's extremism might make him the easiest candidate to beat, particularly in a state that is closely divided but still leans slightly to the right (Trump won there in 2016 by 3.5 points). On the other hand, what if he actually won?

I'd argue that Arpaio getting the nomination is the best outcome for Democrats, for the same reasons that can be applied to races elsewhere. First, what is the real downside? For all the prestige of the office, senators don't have a lot of independent power. Unlike mayors, governors, or presidents, they don't have a bureaucracy and a budget at their disposal to indulge their nefarious impulses. What damage would a Senator Arpaio be able to do? He'd give a lot of angry speeches, but when it came time to cast votes, he'd be pretty much like any other Republican. And one way or another, his candidacy will bring national attention, making the GOP seem even more extreme and irresponsible than it already is, particularly to young voters and minorities.

This was the same issue that arose with Roy Moore in Alabama, even before his interest in teenage girls came to light. In that case, Republicans nominated not only their most extreme candidate, but the one who had a scandal waiting to be revealed, the result of which was that Democrats now hold a Senate seat from Alabama.

Even if Moore's case is unique, we've seen this pattern many times in recent years: Republican primary voters gripped in a Tea Party fervor nominate the nuttiest candidate in the race, who then proceeds to lose what would have been a winnable election. There was Todd Akin, who in the red state of Missouri torpedoed his 2012 bid by telling an interviewer that rape and incest exceptions for abortion bans weren't all that important because "if it's a legitimate rape, the female body has ways to try and shut that whole thing down." There was Richard Mourdock of Indiana, who blew his own Senate candidacy two months later on the same subject, saying that if a woman is raped and gets pregnant "it is something that God intended to happen." There was Sharron Angle, who lost a 2010 race to Harry Reid in Nevada after saying all kinds of controversial things, including that "if this Congress keeps going the way it is, people are really looking toward those Second Amendment remedies." And then there's my favorite, Christine O'Donnell of Delaware, who not only inflated her resume but was forced to air an ad that began with the words, "I'm not a witch." For Democrats, these candidates' missteps were like deus ex machinas that appeared out of nowhere to rescue them from electoral defeat.

Now, the fact that those candidates never made it to the Senate is no guarantee that other extremists won't in the future, of course. But in 2018, Republicans could find themselves saddled with even more nutbars than they have in the past. That's because this year is looking so dire for the GOP that any sensible Republican contemplating a run for higher office would decide to sit the election out and wait for a more favorable environment. As Politico recently noted, not only have none of the many Senate Democrats up for re-election in 2018 who are also contemplating a presidential run gained a serious Republican challenger, "Republican leaders have failed to secure their top-choice candidate in eight of the 10 Senate races in states that Trump won in 2016."

The people willing to take the risk are more likely to be the ideologues, the crusaders, and the unhinged. The more controversy they generate, the more an already excited Democratic electorate will become eager to turn out on election day, making the party's goal of taking back the Senate that much easier to achieve. So if you're a Democrat looking with horror at the candidacy of someone like Joe Arpaio, worry not. He's probably the best thing for your party.