House Minority Leader Robert H. Michel (R-Ill.) returned to his Capitol Hill office Monday night after the White House briefing about U.S. air strikes against Libya, turned to aides and said simply, "Get me a copy of the war powers act."

Michel's response was typical as lawmakers, relying on a Vietnam-era law to carve a congressional role in coping with what they called the "new warfare" of state-sponsored terrorism, rallied behind the president's strike against Libya but expressed deep concern about where it may lead.

"I don't think that, when we were considering the war powers act, we ever got into international terrorism," Senate Majority Leader Robert J. Dole (R-Kan.) said in suggesting modifications, including improved consultation procedures.

In general, members of Congress appeared to be groping for a way to influence shaping new policies without seeming to present roadblocks, and there appeared to be no immediate answers, short of a widespread demand for more consultations before such policies are determined.

Some members, such as House Foreign Affairs Committee Chairman Dante B. Fascell (D-Fla.), complained that Reagan's meeting with congressional leaders three hours before the strike did not meet requirements of the War Powers Resolution for advance consultations before U.S. troops are introduced into hostile situations.

Others, such as House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.), said the consultations were adequate.

Senate Foreign Relations Committee Chairman Richard G. Lugar (R-Ind.) said the question was "arguable."

Broad agreement emerged across party and ideological lines that procedures for consultations should be expanded, refined and possibly formalized to assure a congressional role while there are still policy choices to be made.

"Congress must get more information in advance and be able to examine options before they are set," said Sam Nunn (Ga.), ranking Democrat on the Senate Armed Services Committee.

"We really ought to have some vehicle where we could talk about getting into the mix so we're not left out in the cold," Michel said.

Fascell suggested affirmative action by Congress to authorize presidential initiatives, as was done in the case of Vietnam and Lebanon.

"If we are going to have a series of continuing military strikes . . . then we need to look at some more formal process than is called for under the war powers act for Congress," he said.

But pressure was also building for ways to free the president of some constraints of the war powers act in fighting terrorism, especially those that set deadlines for troop deployment.

Dole and several House Republicans are working on legislation that would give the president virtual free rein in responding to specific terrorist attacks or plots.

In connection with this legislation, improved consultative procedures might be considered, Dole said after a closed meeting yesterday between senators and top administration officials on the Libyan crisis.

Some members also questioned how deeply Congress should become involved or wants to get involved.

"This is an area that legitimately belongs to the commander-in-chief . . . . The president can be held accountable and Congress cannot," said House Republican Policy Committee Chairman Dick Cheney (R-Wyo.), White House chief of staff under President Gerald R. Ford.

"If it gets nasty, a lot of my colleagues will run for the hills," he added.

Rep. Jim Leach (Iowa), a moderate GOP leader, argued that Congress has a role to play but agreed with Cheney on one point.

"Not only has the president reduced Congress to Monday morning quarterbacking, but deep down the majority in Congress like that because that means not taking responsibility for decisions," he said.

Relatively few lawmakers criticized or even questioned the strike against Libya.

Among them were Sen. Lowell P. Weicker Jr. (R-Conn.), who said, "To emulate [Libyan leader Muammar] Qaddafi's policy of killing or injuring civilians undermines this nation's ideals."

Sen. Mark O. Hatfield (R-Ore.) likened the situation to a "a prairie fire which I think is out of control before it really began."

"If there is another act of terrorism, what will we do?" asked Senate Minority Leader Robert C. Byrd (D-W.Va.), saying he fears that retaliation may "strengthen Qaddafi, at least in the short term."