It’s been a few months since the last major Republican threat to shut down the federal government, so with the inevitability of the change of seasons, a new threat is emerging. But this one, touching as it does on a totemic object of enormous power, may be difficult to withdraw or defer once announced.

Yes, it’s the “kill Obamacare or else” demand, and it’s gaining strength, per this report from The Hill‘s Alexander Bolton:

ObamaCare is at the center of a rapidly escalating fight that threatens to shut the government down this fall.

Senate Republicans, including two members of the leadership, are coalescing around a proposal to block any government funding resolution that includes money for the implementation of the 2010 Affordable Care Act….

In the House, 64 Republicans have signed onto a letter pressing Boehner not to bring any legislation funding ObamaCare to the floor.

Sen. Mike Lee (R-Utah), the leader of the Senate effort, predicts the vast majority of the Senate Republican Conference will back his plan, giving him enough votes to sustain a filibuster of a stopgap spending measure.

“This is the last stop before ObamaCare fully kicks in on Jan. 1 of next year for us to refuse to fund it,” Lee said Monday on “Fox and Friends.”

September 30, when existing appropriations run out, also happens to be the day before enrollment in the Affordable Care Act’s insurance exchanges begins.

Alternatively, of course, Republicans could make passage of a debt limit increase rather than appropriations the hostage for an Obamacare defunding, but GOP business allies won’t let that tactic go too far, and debt-limit ultras have already become accustomed to linking that issue to a balanced budget amendment containing some sort of vicious and arbitrary limit on federal spending.

I’m not sure congressional Republicans really want to enter a promising midterm election year just having engineered another phony crisis, but I also don’t know if they can put this particular genie back in the bottle. It’s taken a few years, but the GOP has managed to talk itself into a very firm belief that this national version of Mitt Romney’s Massachusetts health plan is a satanic abomination that will either, depending on which talking point they are following at any particular moment, crash and burn taking the entire U.S. economy down with it, or succeed in seducing Americans to sell themselves into the voluntary slavery of “socialized medicine.”

At a time when major elements of the GOP’s conservative “base” are already convinced–because they hear it constantly from conservative media gabbers–that the only thing standing in the way of total victory for The Cause is the weakness of GOP lawmakers, the “kill Obamacare or shut down the government” war cry could quickly get way out of hand. It doesn’t help that so many conservatives continue to believe, notwithstanding all the evidence to the contrary, that a government shutdown would show Americans how little they actually miss Big Government.

If Mitch McConnell and John Boehner don’t like the idea, they’d better come up with an alternative strategy for dealing with the autumn fiscal “crisis” and give it some momentum. Otherwise the thrill of imagining themselves denying government-enabled health insurance to 25 or 30 million people could so excite conservative activists that there will be no stopping them.