WITH ACTUAL CAUCUSES and primaries just a few weeks away, political junkies are seizing on every wisp of a poll in hopes of learning early the results. They shouldn't count on it. It's entirely possible that the Iowa caucus goers and New Hampshire primary voters have not even made up their minds yet. In some cases they may not have even heard of the candidate they'll vote for, just as a lot of the New Hampshire Democrats who gave victory to Gary Hart in 1984 knew little or nothing about him a week before they voted.

For Iowa, keep in mind that only about 200,000 people in a state with 1.3 million general election voters actually turn out in the caucuses. Poll takers try to narrow down their group of respondents to likely caucus goers. But many people who want to sound civic-minded will tell you they'll attend but don't, while others who now have no intention of attending will be recruited by a friend or neighbor or by some candidate's efficient organizer. So almost every Iowa observer expects candidates who are well organized but have been getting only single digits in the polls -- Pat Robertson, Bruce Babbitt -- to do better on caucus night, and they expect the notorious but unorganized Gary Hart to do worse.

New Hampshire polls are probably a more accurate indication of where that state's primary voters are today, because turnout is high and you can be pretty sure the sample is representative of the primary electorate. But we also know that opinion can move fast and late in New Hampshire in response to campaigning and to the results in Iowa and the Lesser Antilles. George Bush and Michael Dukakis continue to win support from impressive percentages there, and from voters who know a fair lot about them. But when the pollsters ask how many strongly support their man, the strong Bush and strong Dukakis support is 20 percent or less. About 70 percent of both parties' primary voters are weakly committed or undecided.

As for polls in the Super Tuesday South or the rest of the nation, they're interesting and tell us a few things. Jesse Jackson's support from black voters is wide and deep, and Albert Gore has struck a chord with some voters in the South. But don't bet big money on these polls alone. Voters will know a lot more about these candidates by March 8 than they do today. The polls can measure current opinion pretty accurately, but when opinion is wispy so are the poll results.