LAW WEEK COLORADO

The U.S. Supreme Court on Monday struck down three key provisions of Arizona’s tough new immigration law and a fourth may not survive further court challenges.

In a 5-3 ruling, the court said that Arizona mostly over-reached with its 2010 law because the power to regulate immigration belongs solely to the federal government.

Arizona sparked a national debate on immigration policy when it passed the law. Lawmakers in the border state complained that the federal government wasn’t doing enough to control illegal immigration, and took matters into their own hands. Lawmakers in several other states adopted similar laws.

The Obama administration sued Arizona to overturn the law. In its ruling on Monday, the court left standing a provision that requires police officers to check the immigration status of people during lawful stops. However, the court said this provision is still subject to challenge in a lower court.

The court struck down other provisions on the grounds that they are pre-empted by federal law. Those provisions:

* Made it a crime for someone to be in the country illegally. Federal law already makes this a crime, the court noted.

* Made it a crime for undocumented immigrants to apply for a job or work in Arizona. Only the federal government can make this a crime, the court said.

* Allowed law enforcement officials to arrest someone without a warrant if they believed the person committed a crime that could lead to deportation. Only the federal government can authorize this, the court said.

Justice Anthony Kennedy wrote the majority decision in Arizona v. United States. Justices Antonin Scalia, Clarence Thomas and Samuel Alito Jr. each issued their own dissents.