Spoiler alert: He’ll let us down.

Senate Minority Leader Mitch McConnell promised a ballroom full of activists Thursday that he would fight “tooth and nail” for a conservative agenda if he takes the helm of a Republican majority next year…

“If I’m given the opportunity to lead the United States Senate next year, I won’t let you down,” McConnell said. “I will lead with integrity, we will fight tooth and nail for conservative reforms that put this country back on track, we will debate our ideas openly, we will vote without fear, and we will govern with the understanding that the future of this country depends on our success.”

Oddly enough, his reception in the hall today was “lukewarm.” Serious question: What would McConnell have to do, or not do, as Senate majority leader for tea partiers to say, “He was right, he didn’t let us down”? He’ll happily hold a vote to repeal ObamaCare, which will either be filibustered by Democrats or die on Obama’s desk. He might be willing to stand his ground on spending cuts, veto or no veto. Is that good enough? Ain’t no way he’s going to shut down the government or let Treasury hit the debt ceiling, and the closer we get to 2016 the surer that is. So if that’s the litmus test, consider him having failed already.

Actually, I think there are two litmus tests, neither of which has to do with fiscal standoffs. One is on Supreme Court (or cabinet) appointments, the other is on immigration. If Obama gets a vacancy on the Court and nominates someone far enough left to alarm grassroots righties but not so far left that GOP centrists like Mark Kirk won’t vote for him/her, McConnell will face a ton of pressure to keep the nomination off the floor. I think there’s a fair chance that he’ll pass that test. In fact, Obama himself might anticipate it by nominating someone radical-ish in the expectation that he or she will be torpedoed and then nominating the person he really wanted all along as a “moderate” compromise back-up pick. On immigration, though, it’s unfathomable to me that McConnell would block an amnesty bill passed by the more conservative House, knowing that there are more than enough amnesty fans in the Senate to break a filibuster on it, purely to pander to tea partiers. The party leadership wants immigration done by the time of the next presidential election. Mitch the Knife won’t stop them. So yeah, he’ll let you down.

Here he is this morning waving a gun around onstage. I know he feels like he’s being attacked on all sides by conservatives lately, but good lord, man. (Kidding. It was a present for Tom Coburn.)