GOP fights for statehouses in long march to Congress. Democratic statehouses have gerrymandered the GOP into a permanent minority in Congress. Republicans want more say in redistricting after the 1990 census.

Despite George Bush's good prospects tomorrow, a longer-range Republican campaign appears to be stalling. The battleground is statehouses around the country. There Republicans are trying to lay the groundwork for controlling Congress in the 1990s.

Republican leaders decided in the early 1980s that to compete in the House of Representatives- that Democratic bastion - they need a voice in drawing congressional districts. And that means winning state legislatures and governorships, which approve redistricting maps.

The target date is 1991, when the 1990 census is complete and congressional seats are redistributed to match the population.

The problem for Republicans is that they find themselves gerrymandered out of US House seats by Democratic statehouses. In 1984, for example, GOP congressional candidates around the country got 49.5 percent of the popular vote, yet won only 42.5 percent of 435 House seats.

``Our only opportunity to ever make significant gains in House representation is to get control of reapportionment,'' says Kathryn Murray, communications director for the Republican National Committee.

The Democrats see it the same way. ``I believe it's absolutely critical to the control of Congress,'' says Tim Dickson, director of Project 500, which is assisting Democrats in states with closely balanced legislatures.

Currently, Democrats control both legislative chambers in 28 states, Republicans in 9, and the chambers are split in 12 states. Nebraska has a unicameral, nonpartisan legislature.

The GOP fares a little better in raw numbers. It counts 2,959 legislators, or 40 percent of the total, in its ranks - a gain of 4 percent since 1983.

In governorships, important because governors hold veto power over the redistricting maps, the Republicans have gained eight states since 1983 for a total of 24.

The ambitious Republican goal in 1983, when it launched Project 1991, was to win a majority of state legislatures by completion of the 1990 census. Now the goal, somewhat deflated, is to be competitive in a majority of states.

The targets of opportunity this week, when roughly 80 percent of state legislative seats are up for reelection, are about evenly balanced for Republicans and Democrats.

Even though the presidential tide is running with the GOP, the party ambition this election is merely to hold on to the chambers already controlled and to add some seats in chambers where Republicans are still weak.

Further, polls suggest that three Republican governorships - in Indiana, West Virginia, and Utah - are in serious jeopardy next week.

The historic pattern is that the party balance in statehouses ebbs and flows with presidential election years. The party winning the presidency typically picks up around 10 legislative chambers, and loses them during off-year elections, according to William Pound, executive director of the National Conference of State Legislatures.

But this coattail effect appears to be losing its power through the 1980s. The GOP picked up seven chambers in 1984 during a Reagan landslide, raising the hopes of party strategists for 1991. But the Democrats gained six in 1986. The Republicans gained one in 1987.

This year, Mr. Pound expects a relatively small shift one way or another, which, he adds, ``is not boding well for the GOP.''

Even if the pace is slow, however, the Republican Party is still gaining strength on the Democrats, especially in the growing Sunbelt. ``That's probably essential,'' says Pound, ``and should be of concern to the Democrats.''

The 1990 census is expected to take as many as 20 congressional seats away from Northern states and distribute them in the Sunbelt. The likely losers: New York, Pennsylvania, Illinois, and Michigan. The new seats will probably be in Florida, Texas, California, and Arizona.

The statehouses of the South remain a bastion of Democratic dominance, but Republican gains have been steady. In the Florida Senate, 10 Republicans faced 30 Democrats in 1985. Now 15 Republicans face 25 Democrats, giving the GOP plenty of votes to support a veto by their Republican governor. Texas Republicans were nearly invisible in the statehouse a decade ago. Now they hold over a third of the House seats.

The key battles this year:

The Democrats are defending vulnerable majorities in the Pennsylvania House, the Illinois Senate, the Wisconsin Senate, and the Oregon House. The Republicans are holding slim edges in the Pennsylvania Senate, the Ohio Senate, the Indiana House, and the Washington Senate.