In the national debate on immigration reform, Gutierrez, a Chicago Democrat, has long been one of the most vocal politicians, advocating comprehensive reform that both discourages companies from hiring undocumented immigrants and provides a path to legalization. Yet in becoming a central voice against legislation in a state far from his district, he’s triggered the praise of some and the scorn of others.

At issue is a controversial bill passed the Arizona Senate on Monday that would enable police to question anyone they reasonably suspect is in the country illegally, and to charge people with trespassing for being in Arizona without proper documentation.

Critics say the bill invites racial profiling, but proponents say it fills the void the federal government has created by not addressing immigration or enforcing current law.

Arizona Gov. Jan Brewer has until Saturday to sign the bill into law, veto it or do nothing and let it become law without her signature. A spokeswoman for the governor said Thursday that no decision has been made.

In recent weeks Gutierrez has given countless television and print interviews, penned an editorial and released a statement pushing Brewer to veto the bill. It’s a move that raises the question of which government entities should be making and enforcing immigration policy.

“The federal government is in charge of immigration, period,” Gutierrez said in an email Thursday. “As a Member of Congress, my role is to keep the pressure on at the highest levels of government so we get closer to the day our immigration system lives up to our values as a nation.”

Closer to home, Gutierrez’s critics say it’s not his place to intervene in Arizona lawmaking.

“He should mind his own business,” said Rick Biesada, director of the Chicago Minutemen Project. “He should take care of his own constituents in Illinois. Why would he be concerned with Arizona?”

Others have gone further, claiming that the immigration policy Gutierrez advocates undermines U.S. sovereignty and amounts to thinly-veiled amnesty for undocumented immigrants.

“Luis Gutierrez is the poster boy for illegal immigration,” said Dave Gorak, executive director of Midwest Coalition to Reduce Immigration. “Gutierrez represents the interests of those who stop at nothing to prevent our government from enforcing its own immigration laws.”

But those who see the legislation as extreme and inhumane welcome the Congressman’s vocal stance, even on an issue in a state thousands of miles away.

Catherine Salgado, director of communications for the Illinois Coalition for Immigrant and Refugee Rights, said Gutierrez has been one of the few in Congress to bring the issue of immigration to the national level and fight for the rights of immigrants. 

“It is important for those states that are implementing or planning to implement such extreme laws to hear from everybody across the country,” Salgado said. “Any extreme anti-immigrant legislation can be spread across the country.”

Legal experts say it’s not inappropriate for Gutierrez to argue against a state bill that addresses a federal issue.

“He’s a U.S. Congressman, he’s saying, ‘Arizona folks, you should stay out of this business,’” said Kevin Johnson, professor of law and Chicano studies at University of California at Davis. “It’s not surprising to me that someone from the federal government who’s entrusted with immigration regulation is suggesting to a state government that it’s not their job.”

Both Johnson and Kathleen Kim, who teaches immigration law at Loyola Law School in Los Angeles, said they expect that if Brewer signs the bill into law, it will be immediately challenged in the courts.

“There are various constitutional challenges that could be made against the Arizona legislation including equal protection and potentially Fourth Amendment violations,” Kim said. “Arizona gives a very extreme example of where states can go with punitive immigration reform when the federal government fails to reform our broken immigration system in a comprehensive manner.”

Arizona politicians aligned with Gutierrez in opposition to the bill have welcomed his voice into the debate, including U.S. Rep. Raul Grijalva, D-Tucson, who sits with Gutierrez on the Congressional Hispanic Caucus.

Grijalva and Gutierrez gave a joint press conference Tuesday in Washington to urge President Barack Obama to call for a veto of the Arizona bill and pressure the president to pass comprehensive immigration reform.

“We believe the bill has national implications, and we welcome Rep. Gutierrez’s help in making sure that this doesn’t stand,” Grijalva’s communications director, Adam Sarvana, said in a statement Thursday.

It’s a national issue to Gutierrez not because he fears similar legislation might come to Illinois, but because he says it is important to his constituents to support justice and the civil rights of people everywhere.

“It is difficult for politicians to hold elected office if they hold strongly anti-immigrant views on our state and especially in Chicago,” Gutierrez said Thursday. “In Illinois, you could not pull the type of legislative and political stunt the Republicans are pulling in Arizona.”