Jesse Jackson has managed what every politician must crave but what few can achieve: the ability to dominate the discussion even in absentia.

Jackson, of course, was in town for the Congressional Black Caucus 13th legislative weekend, but he seemed almost to play down his presence. As he did last month, at the 20th anniversary of the March on Washington, he once again passed up a shot at "capturing" a major event by announcing his candidacy for president.

He would take a leave of absence starting today, he said, to devote full time to his run/don't run decision. Not much news there.

And yet, in the corridors of the Washington Hilton Hotel, site of the caucus weekend, in the restaurants and bars, even in the legislative workshops, the talk was of "Jesse." Will he run? Should he run? Can he run with enough success to make the effort worthwhile?

Nothing approaching a consensus emerges from these endless arguments, perhaps because the positions taken and defended have less to do with facts (on which there is general agreement) than on the political attitudes of those doing the arguing.

There are the ultrapragmatists (if your favorite can't win, vote for the least-awful candidate who can) and their tunnel-vision soul mates (the only thing worth discussing is how best to defeat Reagan). Those who hold this view tend to see Jackson's candidacy as a distraction--and tend also to complain of being taken for granted by Democrats and ignored by Republicans.

There are the primary tacticians, whose dream is that Jackson would do well enough in enough state contests that he would arrive at the Democratic nominating convention with significant bargaining strength. They shy away from suc questions as what Jackson might realistically bargain for that wouldn't automatically be included in any Democratic platform--except for personal power --say the right to name a quarter of the Cabinet.

There are the despairing militants who see value in consolidating black political power, even in a losing cause, because at the very least it would expose white people for the bigots they are.

Probably the most intriguing and fastest-growing group is made up of the grand strategists, who, while they are solidly anti-Reagan, see Reagan as only a symptom. The disease, they say, is the dependence of blacks on the benevolence of whoever occupies the White House.

A Jesse Jackson candidacy would inspire millions of previously unregistered blacks to get on the voter roles, and that would inspire hundreds of previously unelectable blacks to declare their candidacies for offices ranging from the local courthouse to the statehouse to the House of Representatives.

Jackson would lose, these theorists acknowledge, but enough of those whose candidacies he inspired would win that even a second-term Reagan would have to change his act.

There is one other group in the discussion. I'm not sure what to call them, but they state their position with a question: Where's Jesse going to get the money to finance a campaign?

It may be the question foremost in Jackson's mind these next days and weeks.