There was a time not too many months ago when the fledgling Kennedy-for-president forces looked at Minnesota as a perfect place to ambush Jimmy Carter in the backyard of Vice President Mondale.

The state has a history of supporting political liberals and was the site last June of the first national gathering of a Kennedy draft movement, led by an articulate Minnesota congressman Richard M. Nolan. As late as September, state Democrats favored Kennedy over Carter by a 55 to 40 percent.

But Kennedy has almost disappeared as a force to be reckoned with in Tuesday night's Democratic-Farmer-Labor precinct caucuses. Nolan has all but dropped out of politics recently announcing he will not run for reelection. And a poll released by the Minneapolis Star today reported Carter leading Kennedy by almost 6-to-1.

The only real challenge to the Carter-Mondale ticket in the 4,000 caucus meetings to be held in town halls, schoolhouses and living rooms around the state is expected to be a series of uncommitted slates, representing pro- and anit-abortion forces, and a series of other single issue groups.

Meanwhile, a newspaper poll indicated that George Bush has cut deeply into Ronald Reagan's once comfortable lead in the state, and has emerged as the favorite to win the Independent-Republican causes. The poll taken Friday, showed Bush leading Reagan by 2 to 1 in the Minneapolis-St. Paul area, and running neck-and-neck with him in the rest of the state.

State Republican chairman Vern Neppl, a Reagan supporter in 1976, said the Reagan effort was severely damaged by the candidate's failure to campaign more in Minnesota. Reagan has made two brief appearances here since November.

The Minnesota caucuses have been completely overshadowed by the New Hampshire primary held the same day. They have received only passing attention from the national media and have been largely ignored by most of the candidates.