Top Democrats moved into position for potential runs at the 1992 Democratic presidential nomination Tuesday with runaway wins, but the hopes of Sen. Bill Bradley, D-N.J., may have been undercut by his struggle against a Republican sacrificial lamb.

Even a few months ago, the prospect of running against President Bush scared off the Democrats' big-name candidates, who were waiting for the perfect moment to get into presidential politics.All of the talk centered on fielding a token candidate, perhaps the 1988 vice presidential candidate, Sen. Lloyd Bentsen of Texas, and holding back their strongest challengers for 1996.

But that attitude changed in the weeks before the election when Bush's sky-high popularity plummeted dramatically when he deserted his "no tax" pledge, the economy went into a tailspin and he confounded voters with his almost daily shuffling of campaign themes.

All of a sudden, 1992 looks much better for the Democrats and it would be surprising if some of them do not gear up, and rather quickly, their presidential campaigns.

At this stage of the election process four years ago, Rep. Richard Gephardt of Missouri was commuting to early caucus and primary states and former Arizona Gov. Bruce Babbitt had taken up residence in Iowa.

The one Democrat frequently mentioned as a presidential candidate who was badly hurt in Tuesday's election was Bradley, a Rhodes scholar and former pro basketball player.

Bradley, the prohibitive favorite, barely won a third term against Christine Todd Whitman, a Republican sacrificial offering. Bradley raised $12 million and spent $10.5 million on his campaign. Whitman scrounged up $600,000.

But Bradley became the unwitting victim of a backlash against the $2.8 billion tax raise imposed by New Jersey Gov. James Florio, a fellow Democrat.

A CBS exit poll showed that New Jersey voters by 48-41 did not think that Bradley would make a good president.

The other Democrats frequently mentioned as possible 1992 presidential candidates fared far better and showed once more their vote-getting clout.

Sen. Sam Nunn, D-Ga., the chairman of the Senate Armed Services Committee, was so strong the Republicans did not even field a candidate.

New York Gov. Mario Cuomo, the candidate most party leaders would like to see run, won against two opponents, but by a surprisingly small margin, probably the result of the state's financial problems.

Sen. Albert Gore of Tennessee who lost in 1988, and Sen. Joseph Biden of Delaware, who had to pull out of the race two years ago after acknowledging plagiarizing a speech, won re-election easily.

And Jesse Jackson, who won numerous primaries in 1988 before losing the presidential nomination to Massachusetts Gov. Michael Dukakis, was elected "shadow senator" for the District of Columbia, the first office for which he has been elected.

Gephart also was an easy winner but promised not to run in 1992 when he was elected House Democratic leader.

The elections did not produce a new shining star for the Democrats, but not all the possible presidential contenders were up for election Tuesday.

Senate Democratic leader George Mitchell, Sen. Bob Kerrey of Nebraska, Sen. Chuck Robb of Virginia and Gov. Douglas Wilder of Virginia also could run.

Bush's popularity would have to plunge much deeper and the nation would have to move deeper into a recession before the Republicans would deny him a second nomination.