I hope he wins the primary. As bad as he is, and he’s awfully bad, Republican populists are a thousand percent right that too many of their so-called “representatives” in Congress don’t really represent them. The Republican Speaker of the House has dedicated his career to trying to reform entitlements while purporting to represent a party whose core constituency consists of old people. He’s worked doggedly behind the scenes for years to pass immigration reform while grassroots activists have screamed for stronger borders, a dynamic that led first to Eric Cantor getting ousted in a primary and ultimately to the nomination of Donald J. Trump for president. Ryan is the apotheosis of the dogmatic conservative who worries a lot — in theory, not in practice — about government spending and not so much about the culture wars. His base’s priorities are the opposite.

So why shouldn’t Sheriff Joe get a Senate seat, or at least his party’s nomination for one? He’s even in sync with the base on his pet issue. As of August 2016, 27 percent of Republicans believed Obama was born in the U.S. versus 41 percent who doubted it. (31 percent were unsure.) Fifteen months later, in December 2017, 57 percent of Trump voters said they thought it was definitely or probably true that Obama was born in Kenya. It’s not like Ryan and McConnell will have the numbers to move major legislation after the midterms; even in the best-case scenario where they continue to control Congress, the House majority is sure to be diminished. If they couldn’t pass anything except tax reform and a gigantic spending bill with the numbers they have now, why not let Senator Joe continue the Hunt for the Real Birth Certificate?

“I don’t talk about it anymore, until I become a U.S. senator,” Arpaio told a group of supporters at the Western Conservative Conference in Phoenix last week. “It has something to do with a document.”…

“So, I’m kind of dropping that right now. But, I’m going to tell you something — 100 percent, we proved that’s a fake document,” he said.

Arpaio suggested that “scientific” evidence would make his case. “We had to go to Italy to get expert advice. It’s a very interesting story,” he teased.

He’ll tell that story if Arizona elects him, apparently. And the birth-certificate hunt might not be his only Obama-related investigation as a senator:

Arpaio also doubts that the former president attended Harvard Law School. “Do you have his transcripts or his record?” he asked when the topic came up.

As for national policy, that’s nitpicking:

Pressed for his views on health care, trade and tax reform, Arpaio batted them away as “technical questions.”

“When you’re asking me now, don’t forget: I just made a decision to run,” he said in an interview in late January. “Instead of looking at the sports page, I’ve got to start looking at the newspaper. I don’t have the luxury of being in Washington, having all these bills, talking to my colleagues. I’m just the outside guy.”

Zero interest in policy, to Trump’s right on culture war and conspiracies. Don’t tell me he can’t win a primary. In fact, he might have two shots at it. If McCain steps down because of his health before November, a special election would be called to finish his term. The smart move for Arpaio in that case would be to call up Kelli Ward, the other populist in the race (the third candidate is establishment favorite Martha McSally), and agree that one of them should bail out of the race for Jeff Flake’s seat and run for McCain’s instead. It’s perfectly possible that McSally, forced into a one-on-one battle with someone who enjoys grassroots support, will lose and the GOP will end up with Arpaio and Ward as its two Senate nominees. Odds of Democrats picking up one of those red seats would be very fair. Odds of them picking up both, especially in a national wave year, would be substantial, if smaller.

What’s Trump gonna do? The word last month is that he intends to stay out of the race since he doesn’t want to damage the most electable candidate, McSally, by endorsing Arpaio or Ward but he also doesn’t want to piss off his populist fans by endorsing McSally. McConnell and the party establishment are going to end up begging him to support McSally, though, if the race looks tight in the final weeks, which it probably will. Trump’s going to have Alabama redux on his hands: Back the establishmentarian who might lose anyway or please his base by backing the populist who’ll probably fumble away an easy hold for the GOP in the general election?