For many supporters of the Patient Protection and Affordable Care Act, continued resistance to the law isn’t just mistaken. It’s downright pathological.

They view it this way: Republicans were within their rights to oppose the law while Congress was debating it, but fighting it three years after it was enacted, and more than a year after the Supreme Court ruled it constitutional, is extreme and dangerous. Republicans are “sabotaging” and trying to “nullify” a democratically passed law.

It’s true that because the elections turned out the way they did — with President Barack Obama re-elected and a Democratic majority in the Senate — Obamacare will almost certainly stay on the books for the next few years. It’s also true that, as one might expect in such a heated debate, opponents of the law have sometimes used unwise tactics, hyperbolic language and false claims in attacking it. If you want to say that trying to stop Obamacare by shutting down the government or hitting the debt ceiling is a terrible idea, you’ll get no argument from me.

But there’s nothing wrong with continuing to resist Obamacare even though it has been on the books for three years. What would be strange is if Republicans ended their opposition to it. The law was, after all, passed over almost-unanimous Republican objections. Other large government programs haven’t seen as sustained a campaign against them, but they had more bipartisan support at the outset. Obamacare was unpopular with the public when it passed, and it has only become more so. Republicans generally think it will have bad effects on the economy and on health care. And it isn’t yet entrenched. Why wouldn’t they keep opposing it?

Most of what the law’s supporters call “sabotage” is perfectly legitimate political action. Obamacare’s architects envisioned a lot more cooperation from state governments than they’ve gotten so far. But the law allowed states to refrain from setting up insurance exchanges and from expanding Medicaid. States that exercise those options aren’t disobeying the law or even sabotaging it; they’re just making choices that the law’s supporters wish they would not. State governments can even (as some have) make it illegal for their officials to participate in Obamacare. That’s not “nullification”; it doesn’t require state officials to break any federal law.

Obamacare’s critics are actually doing a better job of obeying the legislation than the administration itself, which has repeatedly found creative ways around the law’s requirements or just acted as though it says things it does not say. Obamacare doesn’t authorize the federal government to offer tax credits and impose certain penalties in states that have opted not to create exchanges. The administration is nonetheless barreling ahead as though it does.

Obamacare’s supporters often suggest that Republicans should try to improve the law rather than junk it. (They say this more and more as the law’s flaws become clearer.) The prospect of improvement, though, is mostly an illusion. It’s not as though some set of major modifications to the law would command bipartisan support. Nor can the law really be pushed in a more conservative direction while retaining its basic character.

A few conservatives have suggested deregulating Obamacare’s exchanges to make it easier to provide policies with high deductibles. But that would mean offering people what the law’s advocates call “skimpy” coverage, which Health and Human Services Secretary Kathleen Sebelius has said isn’t real insurance. Deregulation would also fit poorly with the law’s requirement — one its supporters consider very important — that insurers treat sick people and healthy people exactly the same. Enforcing that rule requires a lot of regulation: What if an insurer offers policies that appeal more to healthy people? If you have a different view of how health insurance should work, you’d need to rewrite the law so much that you’d effectively replace it with something new.

Republicans have too often failed to outline a replacement that would make health insurance affordable for people outside the current system. Even if they do, putting such a plan in place will require years of effort that will often seem futile. It took decades for liberals to get the Affordable Care Act. But no sensible person during that time told them to give up because the matter was settled. Nobody said they should quit out of respect for all the elections that had failed to yield enough politicians committed to their health care plan.

There’s no reason for conservatives to accept rules of the game in which it’s always appropriate to agitate for an expansion of government, but illegitimate to roll it back. Republicans may have all sorts of things for which to apologize, but wanting to scrap Obamacare isn’t one of them.