A federal judge said Monday that she would begin considering whether to allow a legal challenge to proceed against President George W. Bush's terrorist surveillance program.

U.S. District Judge Anna Diggs Taylor in Detroit gave no indication of when she would rule.

On Monday, Taylor heard arguments about the government's motion to dismiss the case on grounds that litigating it would require revealing state secrets.

It was the second hearing in the case before Taylor, who also heard arguments on June 12.

The case was brought by the American Civil Liberties Union against the National Security Agency. The ACLU is asking for an immediate halt to the program, arguing that it violates the rights to free speech and privacy.

The government argues that the program is well within the president's authority, but proving that would require revealing state secrets.

The ACLU says the state-secrets argument is irrelevant because the Bush administration already has publicly revealed enough information about the program for Taylor to rule.

The White House has acknowledged eavesdropping on Americans' international communications without first seeking court approval. Bush has said the eavesdropping is legal because of a congressional resolution passed after the Sept. 11, 2001, attacks that authorized him to use force in the fight against terrorism.

The ACLU's clients include journalists, scholars and lawyers, who say the program has hampered their ability to do their jobs because it has made international contacts wary of sharing information over the phone.