Several American cities have taken the unusual step of suspending trade with Arizona, in protest against the state’s controversial new immigration bill.

Councillors in Los Angeles, San Francisco and Austin voted to cancel official trips and stop doing business with companies based in Arizona.

After hours of grandstanding in the Los Angeles council chambers, in which members compared the statute to Nazism and the imprisonment of Japanese-Americans during the Second World War, the resolution was approved almost unanimously.

“As an American, I cannot go to Arizona today without a passport,” said councillor Ed Reyes. “If I come across an officer who’s having a bad day and feels that the picture on my ID is not me, I can be… deported, no questions asked.”

The law proposed by Arizona Governor Jan Brewer will make it a crime to lack immigration papers and will require police to stop anyone they believe to be in the country illegally. Critics argue this will lead to racial profiling, ostracise legal immigrants and foster resentment between police and the Latino community, but only the federal government has the power to deport people.

“There are a lot of mistruths about the bill,” Brewer said. “You’re not going to walk down the street and get questioned unless you’ve committed a crime.” However, this was contradicted by Arizona’s Pima County Sheriff Clarence Dupnik, who announced that he will not enforce the law. “If I tell my people to go out and look for A, B and C, they’re going to do it,” he said.

“They’ll find some flimsy excuse like a tail light that’s not working as a basis for a stop, which is a bunch of baloney.”

Police organisations are divided. The Arizona Association of Chiefs of Police and the Law Enforcement Engagement Initiative have come out against the proposal, while the Fraternal Order of Police and the Phoenix Law Enforcement Association have offered their support. On Thursday, a group of Arizona Bishops travelled to Washington DC to draw attention to the “moral crisis” in their state and lobby for comprehensive immigration reform.

The bill will become law on July 23, unless attempts to prevent or delay it are successful. The American Civil Liberties Union, the Mexican American Legal Defence Fund and the National Coalition of Latino Clergy are all seeking injunctions to stop it taking effect. If opponents in Arizona can round up 76,000 signatures for a petition, they could force a referendum.

Yesterday, civil liberties groups staged a major demonstration against the bill in Phoenix, bringing in protesters by bus from across the country. But many Americans support tough police action against illegal immigrants.

In a national Pew poll, 59% of respondents said they backed the bill’s provisions. Just 25% approved of the way Barack Obama is handling immigration. An Associated Press/Univision survey, released last week, showed that only 20% of non-Hispanic Americans oppose the law.

Immigration is a particularly sensitive issue in Arizona, which has one of the USA’s most porous borders with Mexico and a rapidly growing Latino population. The state is home to Joe Arpaio, who delights in his reputation as “America’s toughest Sheriff” and runs overcrowded jails full of Latinos, in which male prisoners wear pink socks, pink underpants and pink handcuffs.

In his re-election bid, Arizona Senator John McCain has lurched to the right, to see off a challenge from ultra-conservative ‘tea party’ candidate J.D. Hayworth. Having previously supported a path to citizenship for illegal immigrants, McCain is now running on a promise to “complete the danged fence”.

Comprehensive immigration reform was a key Democratic campaign promise but until now it has been pushed aside. Obama recently admitted that “failure to act responsibly at the federal level will only open the door to irresponsibility by others”, suggesting that the Arizona law would “undermine basic notions of fairness that we cherish as Americans”.

Democrats hope that strident Republican rhetoric about immigration will backfire in the long term. California used to be a swing state, until Republicans passed Proposition 187, which denied illegal immigrants access to health care and public education.

The law was dropped, following persistent legal challenges, but not before it alienated the state’s rapidly growing Hispanic electorate. Columnist Michael Gerson, a former speech writer for George Bush, wrote in the Washington Post that Arizona’s tough new law “must be recognized for what it is: political suicide”. In Arizona’s schools, 40% of the pupils are Latino. In Texas, the figure is 44% and in California, 47%.

“Whatever temporary gains Republicans might make feeding resentment of this demographic shift, the party identified with that resentment will eventually be voted into singularity,” Gerson argued. “In a matter of decades, the Republican Party could cease to be a national party.”