For seven years, Republicans have yearned to dismantle the Affordable Care Act. Now that they have the chance, they seem wholly unprepared to do it right. Much work is still needed to figure out how to avoid destabilizing the health-insurance system. Yet, in their hurry, leaders in Congress seem to want to skip that part. What's the rush?

Republicans are allowing themselves just three weeks to develop a budget bill that would scuttle Obamacare - ending the tax penalties on people who don't have insurance, and scrapping insurance premium subsidies for low-income Americans. Presumably, some or all of the funding to states that have expanded Medicaid coverage under Obamacare would also be cut. Congressional leaders intend to thus lay the groundwork for those changes but then avoid actually making them for two or three years - during which they promise to think up a better system.

It's an unrealistic strategy, because it would give the young and the healthy an incentive to drop their policies, and lead insurers to flee a marketplace undermined by a weakening risk pool and shrinking or disappearing subsidies. Companies can hardly be expected to count on lawmakers' assurances that they'll create a better marketplace later.

Obamacare has been able to expand the number of Americans with health insurance by at least 20 million people and slow the rising cost of health care by addressing the system's inescapable economics: The healthy and relatively affluent need to carry some of the expense of covering the sick and the poor.

In theory, Republicans could create a successful system of their own, with conservative characteristics. But it's a complicated challenge that takes careful, sustained attention. If Republicans start by sending the insurance market into a tailspin, they'll need to spend precious time - and money - on dealing with the consequences.

Republican leaders keep saying that America demands a quick repeal. But what makes them think that? In a poll taken after the election, just 26 percent of respondents said they wanted the entire law repealed. Even Republican voters were split: Only 50 percent of those who supported Trump were in favor of repeal.

Republicans now have the opportunity to shore up America's still unstable health-insurance system - either by amending the Affordable Care Act or creating an entirely new system. Obviously, fixing would be easier, and probably more effective, than rebuilding. What's irresponsible would be to destroy what exists with no clear plan to replace it.