In striking down three of four provisions in Arizona's controversial law known as SB 1070, the U.S. Supreme Court made clear on Monday that the federal government controls the nation's immigration policy -- not individual states.

The decision is a warning shot to states that were tempted to follow Arizona's flawed policies. It also underscores the need for Congress to finally develop comprehensive immigration reform that fits our country's current and future needs.

Although the decision falls short of the desired outright rejection of SB 1070, it stressed the government's discretionary power to decide how immigration policy is enforced. That's a win for President Obama, who recently announced that qualified young immigrants brought into the country illegally as children would no longer be deportation targets -- a humane and long-needed measure.

It's important to note the majority's well-reasoned argument for fiercely protecting federal power. They argued that the country's immigration policies affect trade, investment, tourism and diplomatic relations. In addition, Americans abroad may be put in danger if our country is perceived to treat immigrants harshly and unfairly.

Even before Monday's decision, many Arizonans were rebelling against the dire economic effect that the draconian crackdown was having, including a reported $141 million in lost hotel business because of convention boycotts. Last year, the voter backlash led to the ousting of Republican state Sen. Russell Pearce, the architect of SB 1070.

"This decision should be a big red flag for Minnesota's public servants when it comes to legislating Arizona-like laws," said John Keller, of the Immigrant Law Center of Minnesota. "It ends up in years of litigation and lost convention dollars, taking a huge toll on a state and its taxpayers."

In a 5-3 split decision (Justice Elena Kagan didn't vote), the court determined that Arizona could not make it a state crime for immigrants to be caught without registration documents or to seek a job. Nor could state law enforcement be given the authority to arrest individuals for crimes because they may lead to deportation.

Unfortunately, the justices unanimously refused to strike down the most controversial aspect of Arizona's law, the so-called "show me your papers, please" provision. It gives law enforcement the authority to check the immigration status of individuals detained for any reason if suspected of being in the country illegally.

The ruling on this seemed more a procedural nod than an endorsement of the measure. Justices said the law needed to be tested after it is implemented. It's only a matter of time before an individual detained by police will contest the measure as being unfairly applied and in violation of civil rights -- and the court appeared to welcome such a challenge.

That possibility should slow the momentum of other states and of congressional supporters of "papers, please" provisions. Legislators across the country introduced 865 immigration bills and resolutions in the first quarter of 2012, according to the National Conference of State Legislatures. That number is down from the more than 1,500 measures introduced for the same time period last year.

Mississippi, Missouri and West Virginia rejected bills similar to Arizona's. Whether this is because attitudes are changing or because states have been waiting for the court's Arizona ruling will become evident in the days ahead.

Arizona and other states do have legitimate immigration issues because Congress has failed to tackle immigration reform. President George W. Bush tried mightily but was shot down, even by members of his own party. President Obama pushed for the DREAM Act, but was undercut by Republicans. The paralysis is undermining our country. The court's ruling is a reminder that it's the federal government's role to lead on immigration.