Sen. George McGovern (D-S.D.), who carried the peace banner into presidential politics eight years ago, now decries what he calls "naked, brutal aggression" by the Soviet Union in Afghanistan. He supports a selective military buildup by the United States.

Rep. Morris K. Udall (D-Ariz.), another advocate of military restraint, says he is "a good deal more pessimistic about Soviet intentions" now. He thinks America should establish military bases wherever it can get them.

Sen. Edmund S. Muskie (D-Maine), who has supported accomodation with Russia along with defense spending restraints, shudders as he searches for words to describe his feelings.

"Betrayed, yes, that's the word," says Muskie, "We feel betrayed, used, those of us who -- at some political risk -- traveled that course. It wasn't naivete. We thought it was in this country's best interests. She [Russia] just ran out on us."

Congressional "doves" -- to the extent that the term is even used anymore -- are not so much an endangered species as a mutant breed: talons have emerged under the feathers.

It is not a case of a total molt, however. The McGoverns, Udalls and Muskies still urge restraints and counsel against overreaction, saying global survival depends as much as ever before on finding ways to avoid military and perhaps nuclear confrontation.

But they talk in terms of frustration, anger and betrayal as they reel from events beyond their control that expose them -- wrongly, they insist -- to charges of softness and naivete.

To the extent that they served as the elected embodiment of national qualms about military and foreign policy excesses, influencing policy even when in a minority, they have been set back on their heels. They have had the rug jerked out from under them, and they are scrambling for a new footing.

Sen. Edward M. Kennedy (D-Mass.) may have provided one such foothold on Monday in his Georgetown University speech belittling President Carter's assertion that the Soviet move against Afghanistan was the gravest threat to peace since World War II, McGovern promptly made the same point during a hearing on an Olympics boycott resolution, although McGovern supported the resolution in committee.

Kennedy's call for gas rationing also dovetails McGovern's contention that a strong energy conservation program is the country's best protection against threats to its security from the Middle East and Southwest Asia.

If there is any coherent strategy among those who opposed the Vietnam war and more recently espoused policies of moderation toward the Soviet Union, it is only gradually evolving.

Recent interviews with a half-dozen of them indicate many are in a holding position: advocating selective increases in defense spending along with a generally tougher approach to Moscow, at least until Soviet intentions become clearer.

Probably Udall came the closest to summing up their position. "I've come to the conclusion that, until we know what the Soviet's intentions really are, we have to assume they're ambitious and have entered a new phase of adventurism," he said.

Back in the balmier days when former secretary of state Henry A. Kissinger was touting detente and a new Strategic Arms Limitations Treaty seemed like a good bet, when Richard M. Nixon was visiting Russia and later after Vietnam was abandoned as a lost cause, they had plenty of company. After all, Jimmy Carter promised to cut defense spending in 1976 and was elected president.

Now they are feeling lonely again, especially those who had not begun backpedaling before Afghanistan. The most lonely may be those who, like McGovern, are up for reelection this year, poised on the front lines of exposure to what some, including McGovern, see as a revival of Cold War anxieties.

"What has to be made clear," said McGovern, "is that we're not willing to sacrifice any clear United Staes interest just for the sake of wearing the peace label. I've already made that clear in my state -- that my oppositon to the Vietnam war should not be construed as welcoming the Soviet move into Afghanistan, that it was a case of naked, brutal aggression on their part."

Senate Foreign Relations Committee Chairman Frank Church (D-Idaho), who has been shedding feathers for months in the face of a stiff reelection fight this fall, offersanother defense for beleagured doves. If the Soviets were not deterred by a much clearer U.S. strategic superiority at the time of their moves in Hungary, Czechoslovakia and the Caribbean, why should the size of America's arsenal influence them now? he asks.

But, at the same time, Church, who voted against a 5 percent above inflation increase in defense spending last fall, says such an increase can be justified now -- if "it is spent for what we need," such as conventional as oposed to nuclear weapons.

One apparent reason for the seeming ambivalence in the dove cote is the uncertainty over what the Soviets intend to do beyond trying to solidify their hold on Afghanistan.

McGovern, while saying the United States should prepare for the chance that he is wrong, said he does not believe the Soviets plan to move against Pakistan, Iran or the Persian Gulf area and thinks the Soviets have weakened their hand by alienating the Moslem world.

Muskie is not quite as optimistic, saying, "We've got to be a lot more cautious about Russian assurances . . . [about] our interpretation of their intentions."

One fear that seems to rally most of them is that Congress will go on a binge of defense spending, renewing interest in the B1 bomber, cruise missile, neutron bomb and other examplesof what Udall calls "all those turkey weapons systems" that have so far been kept at bay.

"What we thought were excessive appropriations for defense in the past, well, now I expect they'll exceed even our wildest expectations," said Sen. Mark Hatfield (R-Ore.), a longtime advocate of military resraint.

"The most we can do is try to channel the money in the right direction," said Church, "and we may not win at that."

Despite the political trickiness of trying to draw a line on defense spending during a crisis, Sen. Gary Hart (D-Colo.) who has strayed from the dove ranks since he helped run McGovern's campaign in 1972, thinks it can be done.

He said the Soviet threat, coupled with economic pressures at home, will strengthen the hand of those who, like himself, have been advocating greater selectivity in military spending including providing more mobility in deploying troops.

McGovern, Udall and others rallied to this idea. But they also indicate they might go further.

"If the military makes a reasonable presentation that we need to beef up certain aspects of NATO or strengthen certain naval units, landing units or submarine capability . . . I would be more inclined to support that now than I would have been a few years ago," said McGovern.

Said Udall: "If anyone wants to give us bases -- the Israelis, the Egyptians, the Saudis, or anyone else in that area -- I'm for taking them."

Any move toward reinstituting the draft, however, rubs old wounds raw. McGovern talks about Vietnam-like divisions in the country, and Hatfield suggests acerbically that any draft begin with the over-50 generation.

A return to relatively unrestrained covert operations by the Central Intelligence Agency also draws resistance from Udall and others.

About the only consolation for dispirited liberals will be watching hawk-like fiscal conservatives trying to justify demands for increased defense spending with a balanced budget and tax cut. Other than that, said Udall, "these are not happy times."