In the midst of fast-moving international events, and especially in the midst of a presidential campaign in which the incumbent president's conduct of foreign policy is importantly at issue, it is difficult to have any perspective on how the Carter administration has been performing.

To judge by day-to-day developments, Carter often seems to be fumbling, stumbling through a series of cries he did nothing to anticipate or prepare for. It is not hard to see how columnist Joseph Kraft can write of "the disjointed, almost incoherent character of American foreign policy."

I can easily believe it looks like that to a lot of foreign leaders and governments, both friends and foes. It's not hard to convince me that Jimmy Carter is in foreign affairs way over his head.

But to try to look at today from the perspective of, say, a decade hence, maybe that's not the point. Maybe something else is more important.

If you start from the premise, as I do, that the United States must move away from the quasi-isolationist "never again" mood induced by the Vietnam disaster, that the United States should both quicken and sharpen its involvement worldwide and that this requires a considerable rebuilding of military power, especially conventional but certainly not excluding increases to keep the nuclear balance, then today's situation is not all that disastrous. The reason is that such a major shift in public policy requires strong bipartisan and multigenerational consensus behind it. And that will take, and is taking, a lot of time to achieve. And the way Carter is running things gives us that time.

The one great lighting-bolt conversion in American public attitudes on foreign policy came on Pearl Harbor day. Isolationism of the 1920s variety died in an instant. The post-World War II drift back toward isolationism was halted the day in 1948 when democratic Czechoslovakia succumbed to a communist coup; creation of the Atlantic Alliance and the rearming of the West followed. So did the Cold War.

Vietnam was a seminal struggle pointing public opinion back toward isolationism, implicit in the "Come home, America" theme of George McGovern's 1972 campaign for president. The old impulse, the old tug to mind-our-own-business, avoid-foreign-entanglements, pulled at us once again. Carter came to office pretty much in that mood, pledging, among other things, to cut the "bloated" defense budget after Nixon already had driven it down as well as wasting its assets.

Whether the Soviet invasion of Afghanistan will rank historically, in terms of its influence on American attitudes, with Pearl Harbor or the Czech coup is hard to say. But certainly it has arrested the drift to isolationism among a large number of Americans, beginning with Carter.

Having once expressed pleasure that we had rid ourselves of an "inordinate fear of communism," he has now discovered that communism is not good and that the word of the Soviet leader cannot be trusted. Or so he indicates.

As a result, Carter pledges an American unbrella over a vaguely defined Persian Gulf region, withholds grain and high technology from the Soviet Union, tries to organize a boycott of the Moscow Olympics and boosts the defense budget even though, to fight inflation, all other budgets are ordered cut. The hawks, however, say that he has not done enough, or that much of what he has done is sham. The doves cry that he is recreating the worst of the Cold War atmosphere, proposing to shed American blood for the international oil companies and robbing the nation's poor and defenseless to enrich the military-industrial complex.

The truly important thing, however, is that Carter, for whatever reason, has been no jingo, has taken no irrevocable steps, so that just about everything remains open to debate. He didn't send in the Marines or the 22nd Airborne to rescue the hostages in Iran. The naval task force in the Arabian Sea can vanish quicker than it was assembled; no troops are ashore. The draft registration proposals are not yet a fact of life. Nor is the XM missile. Whether all these uncertainties spring from Carter's lack of foresight and ability is immaterial to my point; the fact is that they keep open the nation's options. A decade hence, this will appear to have been all to the good, I'd venture.

This lack of firm action, of course, upsets the hawks and worries the doves. But it gives time for the uncommitted middle to think it out, argue it out. As a nation, we now are indulging in one of those quadrennial exercises that to foreigners make us seem like mindless idiots. George Ball wants to tidy it up by turning presidential elections back to the vanished bosses. It's all so messy -- and so American. And in the current state of fluid public opinion about foreign policy, I think it's all to the good. In fact, Carter's weakness, in policy conception and ability to deliver, is an asset right now.

As we argue it out, we are registering some tentative opinons by how we vote in the primaries. Of course, there are many other factors involved. Yet with luck maybe the process will produce a policy consensus, reflected in a mandate for the president we elect and in the composition of the new Congress.

So far in this campaign, it seems to me, John Connally's failure is at least partially a repudiation of the let's-punch-them-in-the-nose approach. And Ted Kennedy's failure (Jerry Brown's, too) is at least partially a repudiation of the Afghanistan-is-none-of-our-concern attitude. Ronald Reagan talks of blockading Cuba and about handing out ultimatums threatening "unpleasant" consequences for non-compliance. But he also moves crab-like toward the center by offering to "negotiate vigorously" an arms-control agreement once the military balance is righted. Voters see through George Bush's admonition to stand firm as simply lacking in content. John Anderson's talk of "restraint" appeals to liberal Democrats and independents more than to fellow Republicans. And Carter's managers work to keep him on the high ground in the middle.

The foreign policy issue, the central one of our role in the world of the 1980s, will come into better focus once the two conventions settle on the rival tickets. If we end up, say, with Carter-Mondale against Reagan-Baker, the public will have a reasonable choice between center and right-center. It would not just be Tweedledum and Tweedledee. And it would help produce a sharper sense of American purpose and direction.

Unless, that is, the economy so goes out of control by November that the electorate votes simply to throw out the ins, the Democratic majorities in House and Senate included. Then we would have to take a new look at what such an upheaval would mean for American foreign policy.