Attorney General Eric Holder indicated Sunday that the Justice Department could bring a second suit against Arizona’s new immigration law if it results in racial profiling.

The law, which is scheduled to go into effect later this month, allows state and local law enforcement officers to demand documentation from people suspected of being in the country illegally. The Justice Department has already sued the state in U.S. district court on the grounds that the law pre-empts federal immigration law.

“We wanted to go out with what we thought of our strongest initial argument and to focus on what we thought is the most serious problem with the law as it now exists,” said Holder, who appeared on CBS’ “Face the Nation.” But he said that if the law does go into effect, his department could evaluate whether it results in racial profiling and possibly bring another suit.

Holder also called on Congress for help in bringing to trial suspects in the Sept. 11, 2001, attacks and for funds to close the U.S. detention facility at Guantanamo Bay, Cuba.

He said he still recommends holding a civilian trial for Khalid Sheikh Mohammed, who is accused of masterminding the 9/11 attacks. But he added that funding restrictions imposed by Congress are holding up the case.

“We’re going to have to work with Congress in order, I think, ultimately to bring this case to trial,” Holder said. “And I think that, given the magnitude of what happened on September the 11th and the need to bring justice and closure to this, that people in Congress need to work with us in the executive branch to come up with a way in which we can put these people on trial. Justice has been denied too long.”

Closing the facility at Guantanamo Bay is still a priority, the attorney general said, but the project will similarly need help from Congress. “This is something that we want to do. We need Congressional support in order to do it. We have put in the request that we have for the 2011 budget,” he said, specifying that the administration wants lawmakers to appropriate funds so that it can buy a portion of a detention facility in Thomson, Ill., to house remaining detainees.