That reputation would harden if the Legislature and governor approve a proposal that would draw local authorities deeper into immigration enforcement and further reject the notion immigration is the sole responsibility of the federal government.

The proposal, which has cleared the state Senate and is being considered by the House, would require police to try to determine people's immigration status when they have reasonable suspicions that a person doesn't have legal status.

And, if approved, Arizona would become the only state to criminalize the presence of undocumented immigrants through an expansion of its trespassing law.

While the practical effect of such a law is yet unclear, immigrant rights advocates predict it would lead to racial profiling that would target thousands of Hispanics who are U.S. citizens.

And the proposal's constitutionality is also a source of contention.

A few years ago, police chiefs in two communities in New Hampshire charged undocumented immigrants with trespassing for being in the state. A local judge in 2005 dismissed the charges as an unconstitutional attempt to apply state laws to a federal issue.

But supporters of the proposal say on top of inadequate federal border efforts, many local police departments have turned a blind eye to undocumented immigrants.

Some local politicians "don't have the courage to stand up for their citizens," said state Sen. Russell Pearce of Mesa, the bill's sponsor.

The measure cleared the Senate on a 16-12 vote on June 15 and is being considered by the House. The proposed trespassing provision is similar to proposals vetoed in 2006 by then-Gov. Janet Napolitano, who said she opposed turning all immigrants who sneaked into the state into criminals.

Republican Jan Brewer, former secretary of state for Arizona, became governor in January upon the resignation of the Democrat Napolitano, who quit to head the Homeland Security Department in the Obama administration.

Under this year's proposed trespassing provision, a first offense would be a top-tier misdemeanor punishable by up to six months in jail. Subsequent violations would be a felony that could carry a penalty of up to 2 1/2 years in prison.

Agencies arresting first-time offenders would have the option of prosecuting them or turning them over to federal authorities.

Supporters say the measure wouldn't encourage racial profiling, because officers would still need probable cause to believe people violated the law before they could arrest them.

But opponents say such a law would detract from officers' traditional roles in combating crimes in their communities. They say officers who aren't schooled in the complexities of immigration law would likely approach people based solely on their appearance.

"It's almost impossible for it to be applied without relying on racial profiling and without committing egregious errors," said Jennifer Allen, director of the Border Action Network, an immigrant rights group based in southern Arizona.

And communities could be stuck with legal bills from any mistakes made by officers who aren't trained in immigration law, said Robert DeVries, who is chief of police in the western Arizona town of Kingman, and also president of the Arizona Association of Chiefs of Police.

"It exposes the community down the line if mistakes were to occur," said DeVries, whose group opposes the measure.

As for the constitutionality of the proposal, interpretations are mixed.

Linton Joaquin, general counsel for the National Immigration Law Center, an advocacy group for low-income immigrants, said a state can play a part in immigration enforcement — such as calling federal authorities when arresting an undocumented immigrant on a state criminal violation — but a state can't have statutes that are, in effect, immigration laws.

But Maricopa County Attorney Andrew Thomas, whose office helped draft the bill, said even though the federal government has authority to regulate immigration, states have broad police powers that allow them to contribute to the fight against undocumented immigration. "The argument the states can't do anything to combat undocumented immigration is just wrong," Thomas said.