POLITCALLY, the season resembles the time of the so-called "phoney war" in Europe -- the days and months in 1939 after war had been declared among the great powers but when somehow, for a while, it failed to happen and seemed to exist only in the realm of paper-hat and wooden-dagger play. Just so, Kennedy versus Carter: the Democratic Party is on the verge of a terrific internal conflict, something bound to be really ugly. And yet . . . we are all somewhat bemused by it, not quite ready to credit what we are about to see. A comparable air of cheerful disbelief is found in the public response to news that the Senate minority leader, Howard Baker, has made the centerpiece of his candidacy for president a determination to defeat the strategic arms control agreement soon to come before the Senate for ratification -- thereby ensuring a high-stakes fight that will be even more bitter and consequential than it was shaping up to be.

Part of the bemusement and detachment no doubt is due to the spectator-sport quality of American politics. But this time around the sport is bound to get plenty rough and to have impacts far beyond the usual patronage circles where these transactions are made. Already (interestingly, in view of the fact that these various naughtinesses were supposed to have been reformed away after the Nixon excesses) the unashamed pressures are being brought to bear and purchases of loyalty being made. Florida and Iowa and New Hampshire -- will they crack under the weight of presidential patronage and other assorted largess? What exactly are the prospective Kennedy endorsers being offered or threatened with?

The point is that things are starting early this time and to observe as much is not just to utter one of those aimless laments comparable to a complaint about premature Christmas decorations in the stores. The earliness combined with the fact that the president himself will be challenged, that Sen. Kennedy is risking his place in line this time and therefore must win and that the Republicans sense a real opportunity to come back means that the phoney war is going to resemble the real thing all too soon. And the question is how to limit the damage so far as government is concerned.

If you have any doubt that this is a genuine problem and not just some sniffy, high-minded good-governmentish concern, only consider the effects it has already had. Dick Clark, the defeated Democratic senator from Iowa, whom the Carter people tried to revivify with an important State Department job, has walked off that job to work for Sen. Kennedy. There are charges that he betrayed his original agreement when he did that and countercharges that he only left because the Carter people were requiring political activities of him. You don't need to figure out the accuracy of these allegations to know that it is appalling and disgusting that Mr. Clark's job -- his office was in charge of U.S. efforts to alleviate the Indochinese refugees' suffering -- got sucked into the political whirlpool and was drowned in this conflict of ambitions.

A political year can bring out the better nature of politicians and get them to do decent things they would otherwise never consider. We know that. But the more memorable pressures tend generally to go the other way. Some of that inflation, over which our politicians are ululating and rending their garments even now, had its source in wildly inflationary decisions made by Richard Nixon on the eve of the 1972 election. And the thing has not got any better with time. Do you think the extravagant Chrysler bail-out would have been pledged in a different season? Is the Senate's consideration of SALT really going to be improved by being overlaid explicitly by a political struggle?

We have no cure -- only the admonition, as the formal announcements step up, that the people running for office could do a lot worse than at least to consider some ways in which they might try a little damage limitation, in the Pentagon's immortal phrase. The damage that ought to be limited is the damage to the government's ability to do decent and useful work over the coming year. That doesn't look so promising now. You get the idea that, as it was in another time in Vietnam, some of our political leaders have decided that they have to destroy the government -- to "save" it.