The lawsuit from 15-year Tucson police veteran Martin Escobar is one of two filed Thursday, less than a week after Republican Gov. Jan Brewer signed the law that has sparked fears it will lead to racial profiling despite the governor's vow that officers will be properly trained.
U.S. Attorney General Eric Holder has said the federal government may challenge the law, which requires local and state law enforcement to question people about their immigration status if there's reason to suspect they're in America illegally, and makes it a state crime to be in the country illegally.
Escobar, an overnight patrol officer in a heavily Latino area of Tucson, argues there's no way for officers to confirm people's immigration status without impeding investigations, and that the new law violates numerous U.S. constitutional rights.
Tucson police spokesman Sgt. Fabian Pacheco said Escobar is acting on his own, not on behalf of the department.
The National Coalition of Latino Clergy and Christian Leaders also filed a lawsuit Thursday, and is seeking an injunction preventing authorities from enforcing the law. The group argues federal law pre-empts state regulation of national borders, and that Arizona's law violates due process rights by letting police detain suspected illegal immigrants before they're convicted.
"Mexican-Americans are not going to take this lying down," singer Linda Ronstadt, a Tucson native, said at a state Capitol news conference on another lawsuit planned by the American Civil Liberties Union, the Mexican American Legal Defense and Educational Fund and the National Immigration Law Center.
At least three Arizona cities - Phoenix, Flagstaff and Tucson - are considering legal action to block the law. In Flagstaff, police are investigating a threatening e-mail sent to members of the city council over their opposition to the law. The author said council members should be "arrested, tried in court, found guilty of treason and hanged from the nearest tree!"
About 40 immigrant rights activists gathered outside Wrigley Field in Chicago on Thursday as the Cubs open a four-game series against the Arizona Diamondbacks baseball team. A small plane toting a banner criticizing the law circled the stadium, and activist George Lieu said they've sent a letter to Cubs management asking them to stop holding spring training in Arizona.
A Cubs spokesman declined to comment. Arizona Diamondbacks manager A.J. Hinch says the team is just there to play baseball.
On Wednesday, a group filed papers to launch a referendum drive that could put the law on hold until 2012, when voters could decide whether it is repealed.
The legislation's chief sponsor, Republican Rep. Russell Pearce, said he has no doubt voters will support the new law at the ballot box, which would then protect it from repeal by the Legislature. In Arizona, measures approved by voters can only be repealed at the ballot box.
Meanwhile, the effect of the law continued to ripple beyond Arizona.
A group of conservative state lawmakers in Oklahoma are considering pushing a bill similar to Arizona's. In Texas, Rep. Debbie Riddle, a Republican, said she will introduce a measure similar to the Arizona law in the January legislative session. And Republicans running for governor in Colorado and Minnesota expressed support for the crackdown. "I'd do something very similar" if elected," Former Rep. Scott McInnis, told KHOW-AM radio in Denver.
The Denver Public Schools system is banning work-related travel to Arizona. Even though school employees are in the country legally, DPS spokesman Kristy Armstrong said officials don't want them to be "subjected to that kind of scrutiny and search."
Retired South African archbishop Desmond Tutu also chimed in, saying he supports the idea of a boycott of Arizona businesses, according to a letter he wrote that was posted Wednesday on TheCommunity.com, a website for Nobel peace laureates that promotes peace and human rights.
"I recognize that Arizona has become a widening entry point for illegal immigration from the South ... but a solution that degrades innocent people, or that makes anyone with broken English a suspect, is not a solution," Tutu said.
Colombian singerto meet with the city's police chief and mayor over her concerns that the law would lead to racial profiling.
More Coverage of the Immigration Debate: