Didn’t the Republicans force President Obama to cut spending by refusing to raise the debt ceiling in 2011?

That’s right: That was the origin of the sequestration that has been starting to take effect this year. That episode, though, illustrates how little leverage this kind of tactic creates. First, Republicans had to give the Democrats more than just a debt-ceiling increase. They also had to agree to defense cuts most Republicans disliked. Second, the cuts were nowhere near as momentous a change as a halt to Obamacare would be. The country is not going to look much different in 2035 because of the sequestration. It would look a lot different if Republicans were able to delay Obamacare indefinitely or repeal it (which would be the point of getting a one-year delay now). Third, that was a few months after Republicans had picked up a lot of seats in the House and the Senate. This time they’re negotiating after an election in which Democrats gained seats in the House and Senate.

Republicans didn’t get much last time, and this time they’d be asking for more with less political momentum…

Are they right? If defunding is unlikely to work, are we stuck with Obamacare?

Democrats seem to think that once people start receiving benefits from the law, it will become unrepealable — and some Republicans agree. That’s the fear behind the defunding strategy: Even if it is unlikely to work, it’s the only way to stop the subsidies from flowing before 2014. Subsidies put in place never expire, goes the theory.

Obamacare may be different, though. The polls have consistently found public opposition to it. It may raise premiums for more people than it reduces them. It has the potential to destroy insurance markets as people act on the incentives it creates to go without coverage. The subsidies it provides will go to insurers, not their customers, and do not make most medical services free to patients. (The Congressional Budget Office projects that these subsidies will go to only 2 percent of the population in 2014 anyway.) All of these features suggest that the law will continue to be vulnerable for some time.