Obamacare's Republican critics in Congress have argued repeatedly that the law simply won't work, and that its supporters need to face reality. Some of them ought to take the same critical eye to their own plans to defund the law, which are certain to fail.

Defunding the law would be desirable—if it were possible. But the chances are essentially nil that the GOP's strategy would result in that happening. The idea, championed by Sen. Mike Lee (R-Utah) in a letter released last week, is to refuse to support any continuing resolution, or debt limit increase, that does not also defund the health law. No measure to fund the government can pass without the support of Republicans, so the plan is to use that leverage to force Democrats to agree to defund Obamacare.

The obvious problem with the plan is that, despite Obamacare's poor polling, Democrats aren't going to agree to defund their signature law. But the more immediate problem for the defunders is that the majority of Republicans seem wary of signing on to this plan. Lee's letter has just 11 signatories. A similar letter put forth by Rep. Mark Meadows (R-North Carolina) in the House attracted just a little more than 60 votes—not even close to a majority of the House GOP. And while that letter also teed up a defunding fight, it allowed legislators the flexibility to eventually sign on to a compromise that does not defund the health law. Even with more flexibility to negotiate, in other words, most Republicans just weren't willing to commit.

Does that make them spineless? No, it just makes them in touch with reality. Democrats control the Senate, and President Obama holds the veto pen in the White House. There's no way a bill to defund the president's signature achievement—one his administration has been working extremely hard to push past the finish line—at the last minute.

The only leverage Republicans conceivably have here is the ability to cause a government shutdown. But that's the leverage of a man surrounded by cops with a gun pointed at his own head. Some might like the idea of a government shutdown, but it still wouldn't get Republicans any closer to actually defunding Obamacare, becauase they'd lose the inevitable confrontation. There would be a big political showdown, which would almost certainly backfire against Republicans, for reasons that Ramesh Ponnuru lays out here. Republicans wouldn't then end up pushing the president into doing what they want. But they might end up alienating some of the public and perhaps even boosting the president's slouching poll numbers.

This is not a case of weak kneed Republicans running from a fight. No less than Sen. Tom Coburn, not exactly a slouch in the government-cutting, Obamacare-opposing department, told The Washington Examiner's Byron York last Friday that the defunding plan was "not an achievable strategy. It's creating the false impression that you can do something when you can't. And it's dishonest."

To some extent, this is an example of bad tactics and desperation. No one really thinks it will work. Not even most supporters. But it's indicative of the GOP's deeper strategic pickle when it comes to opposing Obamacare, and fighting health policy battles generally. The GOP coalition has agreed on opposition to Obamacare since the law's passage. But when it comes to health policy, that's really the only thing that the party has been able to unite around. And a big part of the reason is that Republicans came late and underprepared to the health policy game. Democrats spent the years between the Clinton health care initiative and Obamacare building a rock-solid health policy infrastructure—itself an expansion of the liberal health policy sphere built following the collapse of the Kennedy health plan in the 1970s—thus ensuring that both the policy apparatus and the votes would be there when the time came. And in 2010, that work paid off. Obamacare passed. Just barely. But it passed. And it's still here today.

Republicans, on the other hand, all but ignored health policy for all those years. Yes, there were think tank wonks and a handful of administration staffers who were deep in the weeds of health policy, but the party and its allies didn't invest in developing ideas or consensus. Your average Republican legislator didn't have a great grasp of the issue, and would have struggled to tell you what the party was actually for when it came to health care.

And in too many instances, that's still the case.

Take a look at this floor speech given by Rep. Pete Sessions (R-Texas) on the day the House GOP voted to delay Obamacare's individual and employer mandates. It's borderline incoherent at times, such as when Sessions says that "the reason why health care has become more expensive is that the Federal Government does not pay their fair share for Medicare or Medicaid. This United States Congress does not adequately pay their fair share for our seniors or for poor people, and so what happens is it's taken out on people that work." Is he arguing that the problem is that the federal government doesn't pay enough for Medicare and Medicaid, two of the most expensive federal programs, and the programs most responsible for the nation's projected long-term debt problems?

Or maybe not. Sessions also argues that Obamacare "will not work in America because America has a vibrant free-enterprise system whereby a person, whether they're an employer or an employee or just as a regular citizen, could contract to get the health care that they would choose to have." This ignores the fact that, thanks to programs like Medicare and Medicaid, government spending already accounts for almost half of all health spending the in the United States. Worse, it comes dangerously close to suggesting that the only serious problem with the American health care is Obamacare, and that everything would be fine if we simply repealed the law.

This is the problem for the GOP when it comes to health policy: It has no idea what it really wants, except repealing Obamacare, and maybe protecting Medicare for today's seniors. (Mitt Romney's primary health policy message, you may recall, was that Obama should not have cut Medicare to pay for Obamacare.) Which is probably why the party is having such trouble fighting a law that's clearly having more than its share of bureaucratic troubles, and why GOP legislators are finding it so difficult to harness the very real public frustrating and confusion with Obamacare. Republicans, having never made the issue a priority, can offer no real alternative of their own except: not this. On health policy, Democrats may not have something that people like, exactly, but they have something. And they have that something because they spent the time to build it. As a party, and as a political institution, Republicans have never spent the time and effort required to unite the bulk of the party, and enough of the public, around a workable alternative. Instead, it has unworkable plans to fight the president's policy.