Via Dan Riehl, people are going nuts over this in the Headlines thread but I don’t know why. He’s not endorsing her over some tea-party primary opponent. She has no primary opponent. He’s endorsing her over the Democrat in the race, Shenna Bellows (whose civil-libertarian cred from working at the ACLU evidently gave Paul no pause).

Even Jim DeMint, who once said he’d rather have 30 principled conservatives in the Senate than a 60-seat majority of RINOs, saw fit to endorse Scott Brown on the eve of his big special election upset in 2010. If Rand can hold an extra Senate seat for the GOP in 2014 by nudging Maine tea partiers to pull the lever for Collins, what’s the harm?

Q: You’re going to join U.S. Sen. Susan Collins for a state party fundraiser today. She’s defended National Security Agency spying programs you oppose, and she’s also running against a Democrat, Shenna Bellows, who comes pretty close to sharing your views on that and other privacy issues. Do you support her, despite disagreement on many of those issues?

A: I wholeheartedly endorse Senator Collins for re-election. I think she’s doing a great job for Maine and for the country. … I don’t really know, exactly, what her position is on the NSA; you’d have to ask her about that.

I just know my position, but I think we’re a big political party. There’s room for not-entire agreement on every issue.

So why are grassroots righties annoyed? Here’s a representative comment from Headlines:

Well, since Collins is running unopposed on the Republican side, it’s logical for Paul to support her over her democrat opponent. However, this is less about “GOP unity” than it is about Rand Paul being desperate to publicly secure his position within the GOP establishment ranks – Republicans would have supported Collins without Rand Paul’s endorsement, so, it’s all pretty meaningless as far as the Maine election goes.

Rand Paul wants to make that everyone knows that he has shifted from the conservative side, to the establishment side – and his ‘wholehearted’ support for Collins is just one more box checked.

Yeah, the “wholehearted” Collins endorsement is interesting mainly as a temperature check on how Paul’s effort to mainstream-ize himself before 2016 is going. Nearly every GOP candidate has a problem with either the establishment or with grassroots conservatives. (The only major contender I can think of who really doesn’t is Scott Walker.) Paul’s problem, needless to say, is with the establishment, who think he’s too dovish, too much like dad, and just too anti-status quo to be a safe pick, so he’s been at pains lately to try to solve it. At some point, between endorsing Mitch McConnell and shifting to a hawkish posture on Russia and running away from Cliven Bundy and making status-quo noises on abortion and ObamaCare, he risks pandering a bit too much to the donor class and thereby irritating his base of righties and libertarians. Backing Collins so effusively when he could have demurred with a simple “I always support Republicans over Democrats” might have been the last straw, definitive proof that he’s “over-correcting.” Bad enough that he’d back McConnell, tea-party enemy number one for the moment, over a grassroots favorite, but to cheer on someone who voted for the stimulus? C’mon.

The risk here isn’t that righties won’t forgive him. He’s already hard at work on a remedial pander, floating a bill to cut foreign aid to the Palestinians unless they recognize Israel’s right to exist. The risk is that he’s putting himself at a disadvantage against Cruz in the battle for tea-party hearts and minds while not reaping any concomitant benefits among the establishmentarians he’s trying to impress. Paul doesn’t expect to win their votes; all he wants is for them to see him as an acceptable nominee, sufficiently status-quo that they won’t unite to destroy him if he pulls an upset in Iowa or New Hampshire. He even met with Romney’s donor network recently, the creme de la creme of the GOP donor class, to make nice. How’s it going so far? You tell me:

The darkest secret in the big money world of the Republican coastal elite is that the most palatable alternative to a nominee such as Sen. Ted Cruz of Texas or Sen. Rand Paul of Kentucky would be Clinton, a familiar face on Wall Street following her tenure as a New York senator with relatively moderate views on taxation and financial regulation.

“If it turns out to be Jeb versus Hillary we would love that and either outcome would be fine,” one top Republican-leaning Wall Street lawyer said over lunch in midtown Manhattan last week. “We could live with either one. Jeb versus Joe Biden would also be fine. It’s Rand Paul or Ted Cruz versus someone like Elizabeth Warren that would be everybody’s worst nightmare.”…

Ted Cruz, whose wife works at Goldman Sachs, is viewed negatively by many in the industry for his support of last year’s government shutdown and scorched earth approach to political battle. Cruz fired up an activist gathering in New Hampshire earlier this month with the kind of provocative populist message that makes bankers very nervous. “The rich and powerful, those who walk the corridors of power, are getting fat and happy,” Cruz thundered. At the same event, Paul argued that the GOP “cannot be the party of fat cats, rich people and Wall Street.”

As a wise man recently said, the first duty of establishmentarians is to the establishment, meaning that stopping Paul (or Cruz) will almost certainly take precedence for rich Republicans in 2016 over stopping Hillary. I guess, in theory, with enough pandering Rand could convince them that he’s marginally better than her, but how much pandering could he realistically do before convincing his grassroots fans that he’s sold out and would be as disappointing to righties as president as Obama was to hardcore lefties? Maybe there’s no way out of this bind.