The U.S. Supreme Court rightly told states Monday that as frustrated as they might be with federal inaction on immigration, they can’t decide to do the job themselves.

In a ruling that should quiet, at least for a few days, the rhetoric of an ideologically driven court, the justices said that Arizona treaded into federal jurisdiction with most every part of its 2010 Support Our Law Enforcement and Safe Neighborhoods Act. That includes making it a crime for illegal immigrants to apply for a job, requiring immigrants to carry documents that show they’re in the United States legally and allowing officers to arrest someone solely on the suspicion that they aren’t.

The court did let stand the “show me your papers” provision of Arizona’s law that required police officers to check the immigration status of someone they stop and reasonably suspect is here illegally. But on that issue the justices far from endorsed the Arizona statute, instead suggesting that state courts examine it and make sure it doesn’t violate federal immigration policy. Justice Anthony Kennedy helpfully hinted that the provision would be acceptable only if it didn’t cause immigrants to be detained longer than the original reason for the stop. Other states with similar provisions, including South Carolina, will need to reexamine their laws with that in mind.

What’s clear is the court’s sound and simple message: Immigration policy is set by the federal government and enforced by federal officials and agents, who are best equipped and trained to do so. Ceding some of that power to states can lead to uneven application of immigration policy, said Kennedy, writing for the five-member court majority.

It also can lead to abusive legislation. Arizona’s was an egregious example of that, and other states followed suit with similar laws that also made it illegal to employ, house or even assist an undocumented immigrant. The laws crippled farmers, who in some states saw crops go unharvested when immigrant workers fled and Americans didn’t line up to replace them. The laws also jarred communities, uprooting established families and hurting businesses that served immigrants.

Now those states – including Alabama, Georgia and South Carolina – will have to largely gut their statutes. States like North Carolina, where lawmakers were prepping to pursue similarly draconian legislation, should put those efforts on hold.

All of which, however, leaves the U.S. with a broken immigration system that Washington has been happy to exploit politically – but not so eager to solve. That includes President Barack Obama, who advocated for immigration reform in 2008 but has not risked the political danger of actually proposing and leading significant legislation on the issue. His presidential opponent, Mitt Romney, hasn’t done any better, offering only the comically impractical “self-deportation” of millions of illegal immigrants.

A more productive approach is an immigration policy that tightens borders and penalizes illegal immigrants with back taxes and fines, but offers them an opportunity to continue to work in the U.S. and, in the long term, earn citizenship. Such reform would benefit taxpayers and offer relief to farmers and immigrant families, as well as the communities they have come to call home.

That policymaking, the court ruled Monday, is the responsibility of federal lawmakers, whose negligence has led to legislation like Arizona’s. It’s far past time they went to work on it.