The decision on the individual mandate handed down today by U.S. District Judge Henry Hudson in the Eastern District of Virginia makes it clear that Obamacare is on extremely shaky legal ground. That’s fitting, because it’s been on shaky political ground for well over a year now. Today’s decision — possibly joined by others in the weeks ahead — is going to strengthen the already strong perception that this law was ill-advised from the get-go and needs to be repealed to make way for a more sensible, consensus-driven program.

Specifically, the judge’s ruling today found that the new law’s requirement that all Americans must purchase government-approved health insurance or face a fine was not a permissible use of the lawmaking authority granted to Congress under the Constitution. In other words, Congress doesn’t have unlimited authority to do anything it wants. Its powers are carefully enumerated. And among them is not the power to force Americans to buy something they would otherwise forgo.

Without the individual mandate, the whole Obamacare edifice crumbles. The judge did not rule that the entire law must be invalidated. But if the individual mandate goes, the insurance regulations — and most especially the requirement that insurers must take all comers without regard to their health status — will never work. Patients could simply wait to enroll in health coverage until they needed some kind of expensive treatment or procedure, and thus pocket the premiums they would have paid when they were not in need of much medical attention.

Still, it’s been clear for some time that repeal advocates should never bank on courts bailing the country out of Obamacare. This issue is far too important to leave to such an unpredictable process. Moreover, even if the mandate and related provisions are gutted by the courts, that would still leave many horribly damaging aspects of Obamacare in place, such as the massive entitlement expansions and the heavy reliance on government-imposed price controls.

Today was a good day. But it’s really just a small skirmish in a much wider war. By all means, every legal remedy should be pursued. But Congress has a responsibility to undo this mess as well, regardless of how the court cases turn out.