ST. PAUL, MINN., FEB. 19 -- Five of the six Democratic presidential aspirants, trolling for votes in next Tuesday's party caucuses, sort of squared off tonight in what was billed as a major debate.

There was not much debate. Rather than a highlighting of differences among the candidates, as occurred in Dallas Thursday, this turned out to be a consensus attack on Reagan administration policies.

Which was just fine with the partisan audience in the World Theater. Sen. Paul Simon (Ill.) got some of the loudest applause of the night when he cited his vote against confirmation of Attorney General Edwin Meese III as part of his leadership credentials.

The event was intended to help guide next week's caucuses, which will begin the process of choosing Minnesota's 86 delegates to the Democratic National Convention in Atlanta.

It was not clear how much guidance the discussion provided. Part of the problem was format: the debaters sat with their backs to the audience, fielding vaguely worded questions posed by Minnesotans filmed at town meetings.

A similar debate, scheduled for Sunday among Republican candidates, was scuttled by the sponsors after only Rep. Jack Kemp (N.Y.) and perennial office-seeker Harold Stassen agreed to appear.

Much of tonight's Democratic rhetoric was predictable. Simon, who says a victory here or in South Dakota's Tuesday primary is crucial to his underfunded campaign, cast himself in the progressive Minnesota mold of the late Hubert H. Humphrey and former vice president Walter F. Mondale, who was in the audience.

Massachusetts Gov. Michael S. Dukakis, a favorite here by dint of resources and organization, talked of economic development and his record as a state budget balancer. Rep. Richard A. Gephardt (Mo.) parried criticism of his trade and agriculture proposals.

Jesse L. Jackson, with Simon a leader on tonight's applause meter, decried economic injustice and corporate tax advantages. He lamented that the debate had not touched on women's rights or drug abuse, which he called major issues.

Former senator Gary Hart (Colo.), sniping frequently at Simon, Dukakis and Gephardt, argued that his 12 years as a senator and his record of proposing new policy ideas entitled him to the nomination. Sen. Albert Gore Jr. (Tenn.) did not participate, choosing instead to concentrate his campaign effort on the South.

The closest the candidates got to real debate was when Simon, Hart and Jackson ganged up on Gephardt over trade policy and taxation.

Simon and Jackson lambasted Gephardt for supporting the 1981 tax cuts sought by President Reagan.

Hart and Dukakis twitted him for promoting trade legislation that they termed "protectionist."

On other issues -- a sound Social Security system, reduced budget deficits, universal health care, jobs and competitiveness -- the candidates were in general agreement.

All contended that Reagan policies on these issues ran strongly counter to popular sentiment and all promised changes if elected.

As Hart put it, "The one thing that does unite us is our condemnation of the administration."