In an unexpected turn, Arizona's tough new immigration law is dividing the Republican Party — while some GOP politicians insist the measure is necessary to curb illegal immigration, others worry that it could trample civil liberties. Here's how six prominent Republicans come down on either side of the question:

1. Sen. John McCain: Arizona's senior senator — long considered a centrist on immigration — says the federal government's failure to "secure our borders" has necessitated the law, which requires police to demand papers from anyone they suspect of entering America illegally. McCain dismisses the notion that police can't enforce the law without resorting to racial profiling. (Watch McCain explain why the law was necessary)

2. House Minority Leader John Boehner: The law "has a 70-percent approval [rating] in Arizona," says Boehner. "I think that we ought to respect the people of Arizona and their right to make their own decisions."

3. Texas state Rep. Debbie Riddle: Riddle likes Arizona's law so much she plans to introduce a similar measure in her own state "to make sure that the safety and security of Texans is well-established." If the Mexican border were adequately secured, she says, neither Arizona nor Texas would "have to take this action."

1. Jeb Bush: The former Florida governor told Politico he understands Arizonans' anger, but that putting the onus on police to check all suspected illegal aliens is impractical, and wrong. "It places a significant burden on local law enforcement," Bush says, "and you have civil liberties issues that are significant as well."

2. Sen. Lindsey Graham: The moderate South Carolina Republican says Arizona's law is probably unconstitutional. He says the measure "doesn't represent the best way forward," although it shows "what good people will do" when they have no better options.

3. Marco Rubio: The conservative Cuban-American Senate candidate from Florida, who has won the enthusiastic support of Tea Partiers, says history shows that increasing government's power leads to abuses, so Arizona's tough law could be used to "unreasonably single out people who are here legally." Rather than a "piecemeal," state-by-state crackdown, America needs a comprehensive federal fix.