Continued from page 1

Mr. Kobach called that laughable, and the dissenting judge in the 2-1 decision at the appeals court level, Judge Carlos Bea, said to accept that argument would give other countries a “heckler’s veto” over state laws.

Brian Bergin, an attorney for Sheriff Larry A. Dever, whose Cochise County includes 83 miles of the Mexico border in Arizona, said he will be watching to see what the justices say about that during oral argument.

“If the administration prevails in its argument that state law can be pre-empted by virtue of the objections of foreign interests, we’ve put ourselves in a position where I guess foreign policy becomes more important than homeland security,” Mr. Bergin said.

Last year, the Supreme Court upheld an earlier Arizona law that requires all businesses in the state to use E-Verify, the federal government’s voluntary database that checks potential hires’ Social Security numbers to determine whether they are authorized to work in the U.S.

In that case, the court, in a 5-3 decision, said Congress specifically left the door open to states to enact business licensing schemes.

Mr. Wildes said the two cases are different and that the E-Verify decision won’t set a precedent for the law enforcement case, but Mr. Kobach said it is an example of concurrent enforcement by states using a federal tool. He also said since that case is now official precedent, he will be looking to see whether the justices who dissented will now feel bound by it.

The list of those who have officially intervened to keep tabs on the current case reads like a who’s who of the immigration movement: Arizona Sheriff Joe Arpaio, who supports the law; two former Arizona attorneys general who opposed the law; the AFL-CIO and the Service Employees International Union, who have taken the lead as the labor movement has embraced legalization; the U.S. Conference of Catholic Bishops, which also pushes for legalization of illegal immigrants; and Rep. Lamar Smith, Texas Republican and chairman of the House Judiciary Committee.

Justice Elena Kagan recused herself from the case in December, presumably because of her work as solicitor general.

Arguing on behalf of Arizona is Paul D. Clement — the same man who argued the recent case for challengers to Mr. Obama’s health care law.