A man holds a United States flag while marching through downtown Atlanta in protest against Georgia's strict new immigration law July 2, 2011. (Erik S. Lesser/AP)

The Obama administration is escalating its crackdown on tough immigration laws, with lawyers reviewing four new state statutes to determine whether the federal government will take the extraordinary step of challenging the measures in court.

Justice Department lawyers have sued Arizona and Alabama, where a federal judge on Wednesday allowed key parts of that state’s immigration law to take effect but blocked other provisions. Federal lawyers are talking to Utah officials about a third possible lawsuit and are considering legal challenges in Georgia, Indiana and South Carolina, according to court documents and government officials.

The level of federal intervention is highly unusual, legal experts said, especially because civil rights groups already have sued most of those states. Typically, the government files briefs or seeks to intervene in other lawsuits filed against state statutes.

“I don’t recall any time in history that the Justice Department has so aggressively challenged state laws,” said Jonathan Turley, a constitutional law expert at George Washington University Law School.

The legal skirmishing comes as immigration emerges as a defining issue in the presidential campaign and Hispanic voters play an increasingly influential role. Most Republican candidates are calling for a hard line on the nation’s estimated 12 million illegal immigrants — and criticizing Texas Gov. Rick Perry for some of his positions on the issue.

President Obama is staking out a position on the other side. He told a roundtable of Latino reporters Wednesday that Arizona’s immigration law created “a great danger that naturalized citizens, individuals with Latino surnames, potentially could be vulnerable to questioning. The laws could be potentially abused in ways that were not fair to Latino citizens.”

The Arizona law passed last year — requiring police to check immigration status if they stop someone while enforcing other laws — triggered a fierce national debate. A Justice Department lawsuit led federal courts to block that measure’s most contested provisions, but similar laws have been approved in recent months in Alabama, Utah, Georgia, Indiana and South Carolina. At least 17 other states have considered such measures this year.

Although Wednesday’s ruling in Alabama was something of a setback, the Justice Department and civil rights groups have been on a winning streak. The American Civil Liberties Union and other groups have obtained rulings temporarily blocking all or key parts of immigration laws in Utah, Georgia and Indiana, with Republican- and Democrat-appointed judges blasting the measures as devoid of due-process protections or for targeting illegal immigrants.

Now, the administration is under pressure from some quarters to intervene in those states, as well as in South Carolina, where a new immigration law is set to take effect Jan. 1. Civil rights groups have been lobbying the executive branch, according to people familiar with the effort, and the ACLU is circulating an online petition calling for federal lawsuits.

Utah, by contrast, is urging the government to stay out of court. Mark Shurtleff, Utah’s Republican attorney general, has met with senior Justice officials, who he said are considering whether to join the civil rights lawsuit as a plaintiff.

“We believe our defense is much better if the Justice Department is not the one saying our law is superseded by federal law,” said Shurtleff, who added that Utah “worked very hard and carefully to make our law different from Arizona” so it is constitutional.

Conservatives have criticized the Obama administration for suing Arizona, and some legal observers said they detect political motives in the administration’s additional legal steps. The White House has been trying to rekindle excitement among Hispanic voters, many of whom have been disappointed over Obama’s immigration policies.

Justice officials have denied any political motives and said they are proceeding based on the facts and the law. Obama and Attorney General Eric H. Holder Jr. have been critical of the state measures, with the president also telling Wednesday’s roundtable, “We can’t have a patchwork of 50 states with 50 different immigration laws.”

Xochitl Hinojosa, a Justice Department spokeswoman, said lawyers are reviewing the Utah, Indiana, Georgia and South Carolina laws and the “legal principles” established in the Arizona case.

“Based on that review and applying those principles, the United States will decide whether and when to bring suit challenging particular state laws,” Hinojosa said.

Hovering over the debate is the possible involvement of the Supreme Court. The U.S. Court of Appeals for the 9th Circuit ruled in April that the most contested parts of Arizona’s immigration law will remain blocked from taking effect, and the high court could decide to hear the case this term. That would mean a decision before the 2012 presidential election.

“My guess is that they will take it,” said Jonathan Benner, a Washington lawyer who has argued numerous cases involving federal-state conflicts. “This is the kind of case that is most interesting to the Supreme Court.”

The other state statutes include a range of provisions, such as authorizing police to question people’s immigration status in certain circumstances, limiting the ability of immigrants to use some forms of identification and criminalizing the harboring of illegal immigrants.

The Justice Department and civil rights groups are arguing that the laws will lead to harassment of immigrants or racial profiling and that they are “preempted” under federal law, which gives the U.S. government control of immigration enforcement.

“You’d have to be crazy to pass one of these laws, knowing you’re buying yourself an enormous lawsuit,” said Cecillia D. Wang, director of the ACLU Immigrants’ Rights Project. She called the Alabama statute, signed into law in June, “by far the most draconian and extreme.”

The Justice Department and a coalition of civil rights groups sued over the law, which requires public school officials to determine citizenship by seeking children’s birth certificates. Civil rights advocates say that will keep some children out of school because their parents will fear being deported.

On Wednesday, U.S. District Judge Sharon Blackburn allowed that provision to take effect, along with other elements of the law, until she can issue a final ruling. But she temporarily blocked other provisions, including those making it a crime for illegal immigrants to solicit work or to transport or harbor illegal immigrants.

Alabama lawyers have backed the law’s constitutionality, and Gov. Robert Bentley (R) on Wednesday called it “the strongest immigration law in the country.” Other states also have defended their laws.

But some judges have been highly critical. In Indiana, U.S. District Judge Sarah Evans Barker in June blocked the two most contested parts of that state’s law. The provisions would authorize warrantless arrests of illegal immigrants in certain circumstances and make it a crime to accept an identification card used by many immigrants.

Barker, an appointee of President Ronald Reagan, called the law “seriously flawed” and said parts of the state’s defense were “entirely fanciful.”

Indiana officials are defending their law, and Greg Zoeller (R), the state’s attorney general, said the judge’s ruling “can be seen as an indictment of the federal government on their failure to enact and enforce immigration policy.”

Staff writer David Nakamura contributed to this report.