The most contentious part of Arizona's immigration law won't take effect until at least July 20.

The U.S. Supreme Court told a lower court Tuesday that the provision's effective date could be pushed back further if the Obama administration seeks a rehearing before the nation's highest court.

The Supreme Court struck down three sections of Arizona's law Monday but upheld its requirement that police check the immigration status of people they stop for other reasons.

Opponents are expected to ask a judge in the coming days to put the requirement on hold while they argue that the law can't be enforced without racially profiling people.

The Obama administration's challenge to the law didn't confront racial profiling and instead focused on whether the Arizona law was trumped by federal immigration law.