Having failed to block Obamacare in Congress in 2010, or to get the Supreme Court to throw it out in 2012, or to beat Obama himself last November, conservative groups have hit upon two last-ditch methods of preventing a large new entitlement program from becoming an entrenched fact of American life.

One is Utah Sen. Mike Lee’s pledge to refuse to fund the discretionary functions of the federal government unless the law is repealed. The other is an effort to bring the law down at the grassroots by encouraging citizen nonparticipation. Or as Dean Clancy of Freedomworks put it: “BURN YOUR OBAMACARE CARD.”

As there are no special cards associated with the Affordable Care Act, this plan will not work on a literal level. But on a practical level, though the odds are slim, it just might succeed. But if that boycott doesn’t succeed, the only people conservative leaders are going to end up hurting are their own followers.

The Lee pledge, while a fascinating gambit in intra-caucus politics, is impossible, as Republican members are struggling to explain to their constituents. Obamacare’s funding is “entitlement” money that gets spent automatically, so congressional Republicans cannot withhold funding. A grassroots boycott, by contrast, really might work.

The issue is that the much-litigated and much-debated “individual mandate” requiring individuals who don’t get insurance through Medicare, Medicaid, or their employer to participate in insurance exchanges isn’t really all that tough. Even someone like Boston University health economist Austin Frakt, whose analysis says the penalties are stiff enough to make the exchanges work, is relying on a penalty rate that will only be phased in over time. The immediate penalties will be smaller and not do much on their own to push people into getting coverage. That creates a several-year window of opportunity during which this element of insurance coverage expansion could unravel.