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.