PHOENIX – A federal judge ruled Wednesday that Arizona authorities can enforce the most contentious section of the state’s immigration law, which critics have dubbed the “show me your papers” provision.

The ruling by U.S. District Judge Susan Bolton clears the way for police to carry out the 2010 law’s requirement that officers, while enforcing other laws, question the immigration status of those they suspect are in the country illegally.

The requirement has been at the center of a two-year legal battle that culminated in a U.S. Supreme Court decision in June upholding the requirement.

Opponents then asked Bolton to block the requirement, arguing that it would lead to systematic racial profiling and unreasonably long detentions of Latinos if it’s enforced.

Lawyers for Arizona Gov. Jan Brewer urged the judge to let the requirement go into effect, saying the law’s opponents were merely speculating in their racial profiling claims, that police have received training to avoid discriminatory practices and that officers must have “reasonable suspicion” that a person is in the country illegally to trigger the requirement.

In her ruling, Bolton said the court will not ignore the clear direction from the Supreme Court that the provision “cannot be challenged further on its face before the law takes effect.” She reiterated the high court’s interpretation that the law might be able to be challenged as unconstitutional on other grounds.

Among the opponents of the law was the Obama administration, which challenged the law based on the argument that federal immigration law trumped Arizona law. The challenge didn’t confront racial profiling. The administration failed to persuade the nation’s highest court to strike down the questioning requirement.

To the supporters of Arizona’s law, the questioning requirement was the most important part of the statute, whose stated purpose was to reduce the problems associated with illegal immigration through enforcement of the state’s policy.

Immigrant rights groups believe the requirement presented the most opportunities for civil rights abuses.

Shortly before the law was to take effect in July 2010, Bolton prevented police from enforcing the questioning requirement and other parts of the statute, ruling the Obama administration would likely succeed in showing federal law trumps the state law.

Brewer’s office said the law is expected to take effect shortly.