And, finally, Flake has one very powerful tool: a vote in a Senate in which Republican margins are razor-thin. To his credit, his fellow Arizona senator John McCain hasn’t just criticized Trump — he acted to stop a crucial part of his agenda that Senate Majority Leader Mitch McConnell was trying to ram through the Senate using undemocratic methods. Flake, who no longer has to worry about a primary challenge, could tell McConnell that he won’t vote for his agenda unless he begins conducting serious oversight of the Trump administration. If he continues to be a reliable vote for Trump’s agenda, conversely, his anti-Trump speeches won’t mean much.

One could object that it’s not realistic to expect a conservative like Flake to vote against Republican policy priorities or to endorse Democratic opponents of even the most Trump-like Republican candidates. Well, maybe, but then Flake can’t have it both ways. It’s now abundantly clear that a Republican Congress will not check Trump in any way. If tax cuts are more important to Flake than constraining Trump, in the end this makes him no different than McConnell, Paul Ryan, and Trump’s other Republican enablers. He’s just being a lot more self-righteous about it.

I really don’t get the “well, he’s a conservative, so you can’t possibly expect him to use his leverage to threaten matters of High Conservative Principle like ‘Obamacare, but worse’ or ‘banks should be able to rip off their customers with impunity’ to demand oversight of Trump” defense. This is…exactly the implicit deal Ryan and McConnell have made: no oversight whatsoever of Trump as long as he’ll sign whatever they put on his desk and pack the federal judiciary with neoconfederates and the executive branch with wingnuts. I don’t see how Flake giving a speech about how Trump is bad but it’s futile to oppose him while being 100% on board with McConnell makes him morally superior. Indeed, I think I prefer McConnell’s unapologetic cynicism. All Flake has done is to increase his speaking fees.