WHAT DO THE results from last Saturday's Wisconsin straw poll tell us about the race for the Democratic presidential nomination? About as much as the results of the exhibition season in baseball tell us about standings in November.

There appear to be two principal reasons for Sen. Alan Cranston's victory, with 789 votes, in the straw poll taken of 2,035 delegates to the state Democratic convention in Milwaukee. One is his unequivocal support of the nuclear freeze resolution. Wisconsin is a state with no old-time political organizations, and the ranks of its Democratic activists are filled with veterans of campaigns against the Vietnam War. But emphasis on the nuclear freeze may not turn out to be such an asset as the campaign goes on. In Mr. Cranston's home state of California, the nuclear freeze ballot initiative lost much of its support when it encountered articulate opposition last fall and passed by only a 52-48 margin. Evidently many voters, when confronted with cons as well as pros, wanted to balance conflicting goals rather than simply endorse what many of its backers admit is a symbolic measure rather than a realistic blueprint for arms control. A single-issue candidacy on this issue may not prove as successful as Mr. Cranston's efforts in Wisconsin.

The other reason for the Cranston victory is the greater enthusiasm of his following. The expected winner, Walter Mondale, got 727 votes, 62 less than Mr. Cranston; one of the former vice president's strategists said, "Our straw-poll prospects lost out to the sunshine." The Cranston campaign paid for delegates' hotel rooms, while potential Mondale supporters enjoyed the sunny weather in backyards in Eau Claire or lake-front parks in Milwaukee. Any test--straw poll, precinct caucus, primary or general election--is partly a test of enthusiasm. But enthusiasm becomes a less important factor as the campaign moves into arenas where large portions of the electorate are involved.

What's odd is that there seems to be a premium also for candidates who generate little or no enthusiasm. Mr. Mondale, with 727 votes, and Sen. Gary Hart, with 443, seem to have come out of Wisconsin more roughed up than candidates Glenn, Askew, and Hollings, who had 54 votes between them. The difference is that the latter three announced ahead of time they weren't campaigning in this state, and kept their word. In presidential politics, unlike baseball, it's evidently better to go zero-for-zero than to get one hit in five at-bats. But in either case, Grapefruit League batting averages are only limited evidence of what the outcomes will be of games that really count.