Governors' races: a left turn for US?

Judging from the way the 1982 governors' races are shaping up, the economy's lackluster performance may be putting the brakes on the momentum Republicans picked up from the 1980 election.

''We may have taken a conservative turn the last six or eight years, and are possibly now swinging back to the moderate and liberal group that had been running the country the last 15 or 20 years,'' says one Democratic strategist.

President Reagan remains personally popular with many voters. But stagnating state economies - once-bulging state coffers in states like Wisconsin and Iowa are going broke - and rising unemployment are helping the Democrats. Even here in the Sunbelt, the tardy sunrise for the economic recovery has drained the verve from many Republican statehouse campaigns.

The situation remains volatile, however, say tacticians involved in the races , with many undecided voters open to candidate appeals and economic news.

By their own count, Republican professionals concede the Democrats a clear edge in 21 contests across the nation, and the GOP the advantage in just five, according to a survey of the 36 governors races by professionals in both parties. The Republicans put the Democrats slightly ahead in four of the six races they rate very close, with another four races, even.

Overall, with just a month of campaigning ahead, the Republicans see the Democrats in front of 25 races, the GOP ahead in seven, with four a dead heat. Similarly, the Democrats see themselves ahead in 27 races, the GOP ahead in seven, with two even.

Emerging trends in the gubernatorial homestretch:

* A ''revisionism'' of favoring mainstream Democrats is sighted. Former governors - Rudy Perpich of Minnesota, Michael Dukakis of Massachusetts, and Bill Clinton of Arkansas are forging strong combacks against more conservative Democrats in primaries, or against Reagan Republicans in November. Much was made of these Democrats' defeats as signs of a conservative GOP wave in recent elections. The comeback Democrats are sounding a note of contrition for having taken voters too much for granted. But they identify themselves as the ''true Democrats.''

* The races themselves are getting nastier. Republican candidates have a hard time coming up with a positive theme. Democrats sense a deepening GOP vulnerability as election day approaches.

''It's still a very explosive election environment,'' says Paul Maslin, vice-president of Cambridge Research Associates, a political counseling firm that aided Mario Cuomo in his upset primary victory over New York Mayor Edward Koch last week. ''Everything clicked in the last 10 days,'' he says. ''Cuomo really did accentuate the differences between himself and Koch - on the economy, the budget cutting under Reagan. There's a lesson in this race - as in the Dukakis race. The people who are hitting these themes and hitting them hard, are benefitting. Cuomo gained 20 points in 10 days against Koch.''

Republicans have their bright spots. In Idaho they hope to break the Democrats iron grip on Mountain States governorships.

In Alabama they think their candidate, Emory Folmar, can win a governorship in the Cotton South. In 1983 two other Cotton South governorships will be decided - Louisiana and Mississippi - which could give an indication of how the South would line up behind Reagan in 1984.

In the big states: The Republicans so far see Texas GOP Gov. William Clements holding off Attorney General Mark White's challenge. And in the Illinois seesaw race, Republican incumbent James Thompson found himself on the up end of the latest independent voter survey.

But California may be eluding the GOP. ''We were closer in California in June than we've been since,'' says one Republican professional of Attorney General George Deukmejian's race against Democrat Tom Bradley, mayor of Los Angeles.

The most stunning upsets appears to be shaping up in the industrial Midwest. Republicans are going into the election holding eight of nine governorships. They now rate themselves clearly ahead in just two farm states (Iowa and South Dakota), with a slight edge in another (Nebraska), with two races even (Illinois and Kansas).