In sizing up the hard-liners now taking over American foreign policy, those of us who didn't start from a hard-line position have a good bit to sort out.

It's not simply that the liberal or moderate or detente position, however it's described, fared poorly at the hands of the Carter administration and was repaid with contempt by the Soviet Union and was repudiated in the November elections.

It isn't even that liberals, to settle on that word, are still a long way from thinking through a new set of positions. These would at once hold to the liberal vision of a peaceful and just international order in which the United States plays a leadership role, and would fold in a more prudent and realistic understanding of the uglier aspects of Soviet power.

No, the embarrassment lies elsewhere. It arises from what I sense to be the pervasive fact that a lot of moderates are privately relieved, even pleased, that Ronald Reagan beat out their man for president. That he has nominated for secretary of state a man they regard as something between a dubious hustler and a cardboard cutout troubles them deep down less than they maintain.

The reason for this is that they have lost confidence not only in their party's chosen leaders but in its inherited ideas. Along with the rest of the country, moreover, they feel that uncertain times lie ahead and they would rather have someone else carrying the responsibility and, if it comes to that, taking the blame.

From many liberals a quiet message is now going out to the country's adversaries: beware, and don't count on us to spare you the full impact of the hardliners now in power. They are almost grimly intent on having the Soviets and the Iranians and the rest realize that they, the liberals, are out of the picture, hoping that such a realization will lead the adversaries to mend their ways. They concede now, after the election, that their own policies might not have been so likely to achieve that result.

Such is the new form if bipartisanship. It means that the working consensus supporting a hard-line policy is probably substantially wider than Reagan's 51 percent of the popular vote might indicate. Many who voted against him will back his foreign policy, or at least tolerate it, perhaps after offering a token challenge at the start. At this moment, they seem less inclined to act as an opposition than to seek out the ground where their ideas may overlap.

It is a curious moment. Many liberals fear that Reagan, with Alexander Haig at State, will err on the hard side. Even if they worry about it, however, they see some value in the Reagan-Haig image of toughness: perhaps it will intimidate Brezhnev, Khomeini and company. Their anxieties advertise and reinforce the inclinations of Reagan that they profess to fear. This is disconcerting enough. Some liberals, however, do not even seem to me truly serious about their own express anxieties. Secretly they are hawks who have lost their earlier certainty, and dread, that there is such a thing as erring on the hard side.

The liberals' falling away from self-confidence, as from power, has yet another dimension. Carter was finally a prisoner of the forces to his right. But Reagan is in no way captive to forces to his left. That whole part of the political spectrum lies pretty much open to his exploitation. Indeed, on certain issues -- development comes to mind -- he may need to use the left in order to offset those people on his right who make him look like a liberal.Some interesting new tactical combinations can be expected.