Rep. Duncan Hunter's bill is the latest step as lawmakers seek to inject themselves into the debate and force their colleagues to take a stand on the contentious Arizona law. One of those moves failed Wednesday when Republicans tried, but failed, to have the Senate vote on blocking the government's lawsuit against Arizona.

Mr. Hunter's bill, for which he started soliciting co-sponsors Wednesday, would stop the Justice Department from pursuing its lawsuit against Arizona until Attorney General Eric H. Holder Jr. submits a plan to Congress outlining how he would bring sanctuary cities into compliance with federal law.

A majority of voters tell pollsters they back Arizona's law, and Mr. Hunter said the government overstepped its bounds by singling out a state he says is only trying to help federal authorities meet their responsibility to enforce the country's borders.

"The federal government is being inconsistent," said the lawmaker, whose district includes San Diego and other areas just north of the California-Mexico border. "They're saying we don't want a patchwork of laws, and that's why they're suing Arizona, but at the same time they allow sanctuary cities ... to passively impede federal law."

Tracy Schmaler, a spokeswoman for Mr. Holder, did not respond to a request seeking comment Wednesday. But in a statement to The Washington Times last week, Ms. Schmaler said the Arizona law and sanctuary ordinances are not the same.

"There is a big difference between a state or locality saying they are not going to use their resources to enforce a federal law, as so-called 'sanctuary cities' have done, and a state passing its own immigration policy that actively interferes with federal law," she said. "That's what Arizona did in this case."

In a subsequent e-mail, Ms. Schmaler said the DOJ would review new local ordinances to determine if they conflict with federal immigration law, which requires states and localities to cooperate with federal authorities on immigration laws. But she was silent on existing policies.

The Arizona law, which goes into effect July 29 unless a court blocks it, requires authorities to inquire about the legal status of any detained person about whom they have reasonable suspicion might be in the country illegally. The law as amended specifically prohibits using race or ethnicity as a reason for suspicion.

Arizona officials have said the federal government has failed in its responsibility to police the borders, and the state is experiencing a crime wave spurred by illegal immigration. They have said the new law is meant to fill in the gaps in enforcement.

Seven lawsuits have been filed against the state, with arguments ranging from a violation of federal prerogatives on immigration to accusations that it will inevitably result in racial profiling.

"The Arizona immigration law is one of the most recent and obvious examples of racial profiling. [The law] states that race or color should not be factors justifying an officer's 'reasonable suspicion' to demand a person's papers, but how else will an officer act on this vague definition of suspicion?" wrote Laura Murphy and Jasmine Elliott of the American Civil Liberties Union D.C. office in a blog post last week.

The hearing on the DOJ lawsuit begins Thursday at the U.S. District Court in Phoenix.

The Arizona law has become a dividing line in the debate over how to tackle illegal immigration. Convinced they have a winning issue, Republican campaigns have eagerly sought to pin down Democratic congressional candidates on where they stand, arguing voters should know whether members support Arizona or the Obama administration. More than 80 members of Congress have signed on to a legal briefing supporting Arizona.

Mr. Hunter's bill would stop the Justice Department from pursuing its lawsuit against Arizona until Mr. Holder submits a plan to Congress outlining how he would bring sanctuary cities into compliance with federal law.

Mr. Hunter acknowledged that his bill faces an uphill battle in the House, where Democrats hold a substantial majority. Asked about the proposal Wednesday, a spokesman for House Speaker Nancy Pelosi declined to comment, noting the legislation had yet to be introduced.

On Wednesday, senators voted 55-43 on a parliamentary move that blocked Sen. Jim DeMint from raising the issue as part of a debate over extending unemployment insurance.

But the South Carolina Republican is likely to try again on upcoming bills.

"It makes no sense in a free country, in a democracy where we're built on the rule of law, for the federal government to try to intimidate the people of Arizona, who are only trying to protect themselves," Mr. DeMint said.

A 2007 report from the Justice Department's inspector general found 15 cities that don't regularly inform federal authorities when they arrest an illegal immigrant, and 10 cities that wouldn't regularly tell authorities when a known illegal immigrant was being released from custody, either of which could be viewed as shielding illegal immigrants from detection.

The IG report said two jurisdictions - Oregon, and the city and county of San Francisco - acknowledge themselves as sanctuaries. It also said many cities categorized as sanctuaries include language in their policies requiring local authorities to cooperate to the extent required by federal law.