THE Democrats appear to have squandered the support of the independent voters , the swing group that controls the outcome of presidential elections. The independents were turned off by Fritz Mondale's ties with the special interests. They looked upon Gary Hart - the ''new'' Hart - with some fascination. He might have won many of them to his side in the fall.
But not the post-New Hampshire Gary Hart who has been devalued by his adversaries within his own party. Not the Gary Hart who has been charged with lack of substance by Democrats, not by Republicans.
One is reminded of this while talking with a man who, for at least one brief, shining moment, had the independents and others of both parties behind him - Eugene McCarthy. Now a poet and wry observer of the American scene, McCarthy is still a most beguiling personality.
It was McCarthy who came out of anonymity in 1968 to establish himself as the leading challenger of President Johnson and the Vietnam war which he espoused.
McCarthy's appeal was broad, much broader than most observers rated it at the time. ''Clean Gene,'' as he was called by many of his backers, was not tainted by ties to those for whom he would later have to be beholden. Indeed, party loyalists pretty much opposed him because he went his own way.
And it was not just the young antiwar group that swelled his ranks. Many voters who saw Vietnam as a no-win war found McCarthy to their liking. Later on, with McCarthy out of the race, many of his supporters ended up voting for Nixon, as a highly respected University of Michigan study of the election disclosed later.
McCarthy's own party wrecked him - led by those who conformed to the old politics practiced by the party. First, it was Robert Kennedy who, with the Kennedy mystique, was able to push McCarthy aside. Then Hubert Humphrey became the nominee.
Humphrey sought to put together the old FDR Democratic coalition, much as Mondale is doing today. It wasn't enough. The less than widely admired Richard Nixon won by a hair. Independents had swung to Nixon.
The ''new'' McCarthy, the McCarthy the public saw when he first burst on the national scene, might have won. His potential base was broad enough. But that was before he was cut up - by Democrats within his own party.
Even a Hart who has felt he has had to make compromises to some special interests to shape a comeback still holds more potential for picking up the independents than does Mondale. This shows up in the polls, where Hart runs even with Reagan while Mondale trails the President. That's why Reagan would rather run against Mondale than against Hart.
Also, exit polls showed that independents plus Republicans taking part in the Wisconsin primary gave Hart his victory there; but in the Wisconsin caucuses, where independents and Republicans were excluded from taking part, Mondale overwhelmed Hart.
Now Hart has less appeal to the independents than he did at first - thanks to his Democratic critics. He must now pull off something like a political miracle to deprive Mondale of the nomination.
For Mondale to win over the independent swing voter, some negative action on Reagan's part will probably be needed. As of now, Mr. Mondale seems to have little prospect of thus broadening his support - as Hart might have done - to proportions that could give him victory in the November election.