A U.S. judge ordered the Secret Service on Monday to disclose records of visits by nine prominent conservative Christian leaders to the White House and Vice President Dick Cheney's residence.

The ruling, in response to a legal watchdog group's suit, could shed light on the influence leaders like James Dobson of Focus on the Family have had on President George W. Bush's administration. It may also affect legal efforts to force the release of visiting records of convicted lobbyist Jack Abramoff and other similar cases.

"We think that these conservative Christian leaders have had a very big impact," said Executive Director Melanie Sloan of Citizens for Responsibility and Ethics in Washington, which filed the case.

"The White House doesn't want to talk about how much influence these leaders have, and we want to talk about how much they do have," she said.

Dobson is one of the most influential opinion leaders among conservative Christians who are at the heart of Bush's political base.

Others whose visiting records were sought included Family Research Council president Tony Perkins, Gary Bauer, who unsuccessfully sought the 2000 Republican presidential nomination, and Moral Majority co-founder Jerry Falwell, who died in last May.

U.S. District Court Judge Royce Lamberth rejected as "misguided" the Secret Service's arguments that disclosing the records would reveal confidential policy deliberations.

The Secret Service is responsible for presidential security and clears visitors for entry to the White House and Cheney's official residence. It also argued that the records were not under its control but were protected presidential documents.