PHOENIX

The Arizona immigration law came under new legal scrutiny in a packed courtroom Thursday as a federal judge considered whether the crackdown should take effect next week amid a flurry of legal challenges.

Judge Susan Bolton did not issue a ruling after two court hearings stemming from lawsuits brought against the law, which has reignited the national immigration debate.

The hearings drew considerable interest as Republican Gov. Jan Brewer and the Justice Department's top lawyer in Arizona both attended, along with dozens of spectators.

Seven opponents of the law were arrested after they sat in the middle of a busy thoroughfare outside the courthouse and unfurled a massive banner that said ''We will not comply.''

Bolton has been asked to block the law from taking effect as she hears several lawsuits that question the constitutionality of the measure.

Opponents say the law will lead to racial profiling and trample on the rights of the hundreds of thousands of illegal immigrants in Arizona. Supporters say the law is a necessary response to combat the litany of problems brought on by illegal immigration and the federal government's inability to secure the border.

Bolton, an appointee of former President Bill Clinton, repeatedly questioned Justice Department attorney Edwin Kneedler to explain how specific provisions of the law intruded on federal authority as he had argued.

''Why can't Arizona be as inhospitable as they wish to people who have entered the United States illegally?'' she said.

Without prodding from attorneys, the judge also pointed out to lawyers the everyday realities of Arizona's immigration woes, such as signs that the federal government erected in a wilderness area south of Phoenix that warns visitors about drug and immigrant traffickers passing through public lands.

She also noted the immigrant smuggling stash houses that are a fixture on the news in Arizona. ''You can barely go a day without a location being found in Phoenix where there are numerous people being harbored,'' Bolton said.

Kneedler said the law's requirements that law enforcement check on people's immigration status set a mandatory policy that goes beyond what the federal government requires and would burden the federal agency that responds to immigration-status inquiries.

Attorney John Bouma, who represents Brewer, said the federal government wants to keep its authority while turning a blind eye to illegal immigrants.

''You can't catch them if you don't know about them. They don't want to know about them,'' he said.

Brewer said she's confident the state will prevail, adding that Bolton ''certainly understands the dangers that Arizonans face in regards to harboring illegals.''

During the morning hearing, Bolton told lawyers for the American Civil Liberties Union that she's required to consider blocking only parts of the law, not the entire statute as they had requested.

ACLU attorney Omar Jadwat said the law's provisions are supposed to work together to achieve a goal of prodding illegal immigrants to leave the state. He called it unconstitutional and dangerous.

Most of the controversy about the law centers on provisions related to stops and arrests of people, new crimes related to illegal immigrants, and a requirement that immigrants carry and produce their immigration papers.

Other parts of the law getting little attention deal with impoundment of vehicles and sanctions against employment of illegal immigrants.

Bouma told Bolton that those challenging the law haven't demonstrated that anyone would suffer actual harm if it takes effect, and that facts -- not conjecture -- must be shown.

''In Arizona we have a tremendous Hispanic heritage. To think that everybody that's Hispanic is going to be stopped and questioned ... defies reality,'' Bouma said. ''All this hypothetical that we're going to go out and arrest everybody that's Hispanic, look around. That's impossible.''

Defendants include various county officials from throughout the state, most of whom sent lawyers to the hearing. Cochise County Sheriff Larry Dever was there in person, sitting at the front of the courtroom.

Dever's county is on the Arizona-Mexico border and he knew a rancher who was killed in March on his sprawling border property by a suspected illegal immigrant, possibly a scout for drug smugglers.

The killing of Robert Krentz in many ways set the stage for the new Arizona law to pass, with politicians calling for action amid border violence.

Before the hearings, opponents gathered in prayer and carried paper doves attached to plants representing olive branches, a symbol of peace.

The law requires officers, while enforcing other laws, to check a person's immigration status if there's a reasonable suspicion that the person is here illegally. It also bans people from blocking traffic when they seek or offer day-labor services on streets and prohibits illegal immigrants from soliciting work in public places.

Since Brewer signed the measure into law in April, it has inspired rallies in Arizona and elsewhere by advocates on both sides of the immigration debate. Some opponents have advocated a tourism boycott of Arizona.

It also led an unknown number of illegal immigrants to leave Arizona for other U.S. states or their home countries and prompted seven challenges by the Justice Department, civil rights groups, two Arizona police officers, a Latino clergy group and a researcher from Washington.