The Supreme Court ruling on Arizona’s tough immigration law, which allows state and local police there to question individuals about their immigration status, will bolster laws in a dozen other states that want to use local law enforcement as a tool to curb illegal immigration, experts and advocates said Monday.

While supporters hailed the court’s decision as a major breakthrough in the battle to control illegal immigration in the absence of an effective national policy, opponents said they feared it would open the door to abuse, intimidation and racial profiling across the country.

“This is good news for the state of Arizona, and it will have an immediate impact on Alabama, Georgia and South Carolina, which have similar arrest provisions in their laws and will presumably have easy sailing in the courts now,” said Kris Kobach, secretary of state for Kansas and a former law professor who co-authored the Arizona law.

“There is no way to enforce this law without racial profiling,” said Edgar Aranda-Yanoc, chairman of the Virginia Coalition of Latino Organizations, speaking to reporters Monday with leaders from several other groups in Falls Church. “Unfortunately, people of color and Latinos will be targeted.”

National advocates on both sides of the debate described the situation in Alabama — the only state that allows police to check immigration status — as a role model or negative example of how Arizona-style laws play out.

In the Washington area, advocates on both sides praised and criticized the long-term results of a similar law that passed five years ago in Prince William County.

The high court decision will not have an immediate impact in any state, including Arizona, because federal courts will need weeks or months to consider and apply the ruling to state laws they have blocked, and because other legal challenges to those laws are expected to be revived.

White House officials also announced Monday that they are instructing federal immigration offices around the country to focus on border security and criminal problems. They said the Department of Homeland Security will no longer issue detention orders for illegal immigrants who have not committed other crimes and will phase out its cooperative agreements with local law enforcement agencies to identify illegal immigrants — starting immediately with Arizona.

However, local and national immigrant rights groups expressed concern that the court decision will help other states pass and implement “copycat” legislation that makes legal and illegal immigrants vulnerable to police pressure and harassment. The Arizona law requires police to check the legal status of almost anyone they encounter if they have a “reasonable suspicion” they may be in the state illegally.

Legislators in Pennsylvania, Mississippi and several other statessaid this week that they had been waiting for the ruling to introduce Arizona-type laws that would withstand legal challenges.

“I am very, very concerned about the ‘show me your papers’ policy. It is going to create discrimination,” said Gustavo Torres, executive director of CASA of Maryland, a regional immigrant advocacy group. He said the ruling made it “more important than ever” for the federal government to pass comprehensive immigration reform.

Immigration experts noted that the high court did not give carte blanche to Arizona’s drive against illegal immigrants. While upholding the right of police to ascertain legal status, it struck down other aspects of the law that conflicted with federal policy, such as making it a crime for an illegal immigrant to seek work or to be in the state without proper documents.

Activists disagreed on the scope and significance of the ruling. Dan Stein, president of the Federation for Immigration Reform, said the ruling — coupled with an earlier decision upholding federal ID checks on employees — means that “states now have broad latitude to carry out a policy of attrition through enforcement” of immigration laws.

But opponents stressed that, in addition to striking down three other sections of the Arizona law, the high court framed a narrow definition of what states can do to enforce immigration law and suggested that in some cases, even police questioning of legal status could still be open to legal challenge.

“The court has issued a sharp rebuke to Arizona and restated the limits on state power to deal with immigration matters,” said Cecilia Wang, a spokesman for the American Civil Liberties Union in San Francisco. She said the ACLU will “go into court immediately” to challenge Arizona and “copycat” laws in other states on grounds of violating immigrants’ rights.

Laws that have been blocked in Georgia, Indiana and South Carolina all have provisions allowing police to question immigrants’ legal status, but all are written slightly differently and some may need to be changed to fit within the high court’s ruling.

National immigrant advocates said the situation in Alabama, where a federal court last year upheld part of a state law allowing local police to check immigrants’ legal status, makes them especially worried about what will happen if other states are allowed to follow suit. Tens of thousands of illegal immigrants have fled Alabama since the fall.

Alabama state Sen. Scott Beason, the state law’s sponsor, said he was “very pleased” that the high court upheld state police powers, but disappointed and confused by parts of the ruling that forbid states from making it a crime for immigrants to be in the state without proper documents.

“I think the court made the issue as clear as mud,” Beason said.

The greater Washington area has also served as a laboratory for tough immigration laws. In Prince William County, the 2007 law originally allowed police to check any individual’s immigration status. After protests, the law was modified to allow police to check the legal status only of people who have already been arrested.

County Board Chairman Corey A. Stewart (R-At Large), who championed the county law and is now running for lieutenant governor of Virginia, said Monday that Prince William had found a “sweet spot” that would allow localities to crack down on illegal immigration without provoking problems. “I would not be surprised ultimately if Arizona goes the same way,” he said.

But local critics of the county law hold a more negative view. Tim Freilich, who heads an immigrant advocacy program for the Legal Aid Justice Center, said the county crackdown had “divided the community, it devastated the local economy.”

Staff writers Luz Lazo, N.C. Aizenman and Sandhya Somashekhar contributed to this report.