RICHARD Wirthlin, the Republican pollster, has detected something quizzical about the mood of America in this election year. Although President Reagan's popularity remains high (about 70 percent) across the country, Dr. Wirthlin reports that the President gets even better ratings in states that have been battered by troubles in the oil, gas, mining, and farming sectors.
In depressed Texas, for example, Mr. Reagan is more popular than he is nationwide, and the same is true in Louisiana, which has the country's highest jobless rate.
Texans aren't upset with Reagan; they're angry with Democratic Gov. Mark White. Louisianians aren't peeved with the President, they're perturbed with their own Democratic state government.
America's present, bifurcated economy (prosperous on the East and West Coasts, depressed in the middle) might have spelled disaster for Republican hopes in Election '86. Instead, it looks as if the GOP could benefit from both prosperity and depression.
If Wirthlin is correct, then this could be great news for the 36 Republican candidates for governor -- and for GOP hopes to eventually become a majority party across the nation.
Major political attention this year has focused on the races for the US Senate. Reagan desperately wants to hold the Senate through his final two years in office.
But in the long run, some political experts say, the most important elections this year may be fought out in states selecting governors and legislatures. That's where the GOP needs to lay its base for power in the 1990s.
There has, perhaps, never been a more opportune year to do that.
Of the 36 governorships involved in this year's election, 27 are held by Democrats and only 9 by Republicans. The GOP has little to lose, and a tremendous amount to gain. Just an even split would bring huge Republican gains.
Further, in 15 of the states, Democratic incumbents are retiring, which means Republicans will be able to run on a nearly equal footing with their Democratic opponents.
All this has raised excitement among Republicans. Gov. Richard L. Thornburgh of Pennsylvania, campaign chairman of the Republican Governors' Association, predicts that at worst the GOP will enjoy a net gain of six seats this year. And the total could go as high at 10.
A gain of 10 would give Republicans a majority of the governorships nationwide (26-24). The current division is 16 Republicans, 34 Democrats, nearly as low as the GOP's post-World War II nadir of 12.
Democratic officials shy away from public predictions on the governors' races, but they concede privately that something in the range of six to seven new Republican seats would not be out of the question.
All this has importance that goes beyond power and prestige in Austin, Texas; Tallahassee, Fla.; or Sacramento, Calif. Eventually, control of the state capitals can be leveraged into control in the Congress.
California provides the most vivid example of turning political control at the state level into political power in Washington.
In 1984, Republican candidates for Congress in California won 4,260,007 votes. Democrats got 4,182,524. Yet Democrats walked away with 60 percent of California's congressional seats, while Republicans got only 40 percent.
Using detailed political information on California's population from the 1980 census, the Democratic-controlled California Legislature had carved the state into 45 districts that gave their party every advantage. It's the process called gerrymandering.
The gerrymander causes Republicans in California to ``waste'' hundreds of thousands of votes, while Democrats efficiently spread their votes for maximum effect.
Thus the Republican candidate in California's 14th, an awkward US House district that stretches from the Oregon border all the way down below San Francisco, got a huge 176,840 votes in 1984 -- far more than he needed for election. But in the California 15th, the Democrat won with a lean 99,287.
Republicans have pulled the same sort of stunt on the Democrats. But since Democrats control most state governments, it is the Republicans who are hurt more.
At present, Democrats control the US House of Representatives by a margin of 252 to 180, with three vacancies. Republicans figure they will never move into the majority there until the effects of gerrymandering are reduced. And that means capturing -- or at least sharing -- power at the state level.
At present, Democrats control 32 state senates, and 32 statehouses, along with their 34 governors. Republicans have 16 Senates, Houses, and governors. One House (Montana) is a 50-50 tie, as is one Senate (New Mexico) at 21-21.
Both Republicans and Democrats would obviously prefer to control both houses and the governorship in a state. Yet the great danger for Republicans when the next reapportionment of US House districts takes place after the 1990 census will be in states where they have neither the House, the Senate, nor the governorship.
Just the governorship, or one of the legislative bodies, might be enough to head off an unfair drawing of district lines. So Republicans are putting their greatest efforts into the governorship races this year, as well as into legislative contests in states like Pennsylvania, where Democrats hold only the narrowest of leads (103 to 100) in the House of Representatives, or Illinois, where Democrats lead in the state Senate by only 31 to 28.
Charles Dolan, executive director of the Democratic Governors' Association, scoffs at GOP plans to capture most states by 1990.
``They've got a top-down party, we've got bottom-up,'' Mr. Dolan says. ``We've got the majority of the city councilors, the majority of the big-city mayors, the majority of the state legislators, and the majority of the governors. They've got Ronald Reagan.
``The mistake Republicans make is seeing Reagan as the key to their party building. Reagan is personally popular, but he is irrelevant to state elections.''
Republican strategists counter that Reagan can raise money, generate excitement, and make a significant difference, especially in smaller states where a presidential visit becomes a memorable occasion. A Reagan visit to South Carolina, Colorado, or Idaho, for example, might help tip the balance in a close race.
As summer turns into autumn, a number of political analysts say that 15 states should be watched closely. Among them are a dozen Democratic states: Alaska, Arizona, Colorado, Florida, Kansas, Maine, Nebraska, New Mexico, Oklahoma, South Carolina, Texas, and Wyoming. Only Texas, with Governor White, has an incumbent seeking reelection. In two others, the governor is stepping down, and in one the incumbent lost in the primary.
Only three current GOP states appear to have close races. They are Oregon and Tennessee, where governors are retiring, and Iowa, where Gov. Terry E. Brandstad is locked in a tight duel with his Democratic challenger, former state Senate majority leader Lowell L. Junkins. A partial, state-by-state assessment:
Texas. This is perhaps the most interesting race. Governor White, struggling against the decline in oil revenues and a collapsed housing market, appears behind. But former GOP Gov. William Clements, his opponent, may have hurt himself with talk of a so-called secret plan to solve the state's fiscal problems.
Iowa. Governor Brandstad still leads in polls, but his showing is below 50 percent, which is very weak for an incumbent. The race is considered too close to call.
Maine. There hasn't been a Republican governor from Maine since 1962, but this time GOP Rep. John R. McKernan Jr. leads by 12 to 14 points.
New Mexico. This is another good Republican shot. Garrey E. Carruthers, a former official of US Department of Interior, leads the Democrat, engineer Ray Powell.
Oklahoma. Former Gov. Henry Bellmon, the GOP nominee, should win this one.
Tennessee. A Republican state, it could go Democratic this year with Ned Ray McWherter, the state House speaker. But former Republican Gov. Winfield Dunn will keep it close to the end.
Florida. Both parties are picking their candidates in a Sept. 30 runoff. Republicans are gaining steadily in the Sunshine State, and the race is considered a tossup.