President Bush has called on Congress to thoroughly review the law that bans the Army, Navy, Air Force and Marines from participating in arrests, searches, seizure of evidence and other police-type activity on U.S. soil. The Coast Guard and National Guard troops under the control of state governors are excluded from the Reconstruction-era law, known as the "Posse Comitatus Act."
Ridge said Sunday that it "goes against our instincts as a country to empower the military with the ability to arrest," and called the prospect "very unlikely."
But he said the government is wise to examine the law.
"We need to be talking about military assets, in anticipation of a crisis event," Ridge said on "Fox News Sunday." "And clearly, if you're talking about using the military, then you should have a discussion about posse comitatus."
Two influential Democratic senators agreed with Bush and Ridge that the law ought to be reviewed, but expressed no interest in granting the military new powers to arrest American citizens.
Sen. Carl Levin, chairman Senate Armed Services Committee, said posse comitatus "has served us well for a long time."
"It's kept the military out of law enforcement, out of arresting people except in the most unusual emergency situations like a riot or after some kind of a disaster where they have to protect against looting," Levin, D-Mich., said on CNN's "Late Edition."
However, he said: "I don't fear looking at it to see whether or not our military can be more helpful in a very supportive and assisting role even than they have been up to now providing equipment, providing training, those kind of things which do not involve arresting people."
Sen. Joe Biden, chairman of the Senate Foreign Relations Committee, said he favors expanding the military's role in responding to major catastrophes such as an attack by a weapon of mass destruction.
The law "has to be amended, but we're not talking about general police power," Biden, D-Del., said on "Fox News Sunday."
Air Force Gen. Ralph E. Eberhart, who heads the new military command charged with defending American territory, told The New York Times he favors changing the law to grant greater domestic powers to the military to protect against terror attacks. He offered no specific changes he favored.
Congress is racing to approve legislation by the end of its session this fall that would make Bush's proposed Department of Homeland Security a reality.
The House Select Committee on Homeland Security approved the measure creating the department by a 5-4 vote Friday night, fracturing the veneer of bipartisanship that had surrounded the issue.
Democratic opposition centered around an amendment delaying this year's deadlines for airports to screen checked baggage for explosives, as well as disputes over whether the new department's chief should have greater flexibility over its work force, and language exempting certain security-related products from lawsuits.
The overall measure would give Mr. Bush most of the power and agencies he sought in the new Cabinet agency. The department would have 170,000 employees and a $38 billion annual budget and serve as the new home of the Coast Guard, Border Patrol, Customs Service, Secret Service, Federal Emergency Management Agency and the just-created Transportation Security Administration.
That bill is to be considered by the Senate committee Wednesday.
House Majority Leader Dick Armey said on NBC's "Meet the Press" there was a strong possibility Congress will resolve its differences and send Bush a bill enacting the sweeping government reorganization by Sept. 11.
Some lawmakers have expressed concern about rushing decisions on far-reaching changes in the bureaucracy, but Armey said: "It's time to move forward with this. The president's got a good plan."
Bush planned to give a speech Monday about his proposed new department and view demonstrations of high-technology devices for combatting terrorism that are being developed at the Argonne National Laboratory in Illinois.