IN THE CASE involving the redistricting of the Indiana legislature -- a case likely to set the standard by which all districting plans will be judged for the rest of the century -- the Supreme Court has stayed the order of the lower federal court requiring a new plan to be drawn. Technically, this means only that Indiana's state legislators will be elected in 1986 from the same districts used in 1982 and 1984. But it also suggests -- doesn't guarantee, but suggests -- that the court will ultimately allow Indiana's current redistricting plan to stand.

That would be a victory in Indiana for the Republicans and, in most other states, for the Democrats, who have had control of more legislatures. It would also be a victory for what we consider the sensible view that courts should not second-guess legislatures on redistricting plans drawn under the discipline of the equal-population standard. That discipline is tight enough to allow opposition parties and factions a chance to take control, given the political ups and downs almost certain to occur in the 10-year period redistricting plans are intended to remain in effect.

The interesting political question now, no matter which way the court rules, is whether the Republican Party will take up the challenge posed by the fact that the Democrats, losers of four of the last five presidential elections, hold 61 percent of the seats in state legislatures. There are some signs they will. In 1983 the Republicans captured the state senate in Michigan, and in 1984 they won the house in Minnesota -- the one state where they didn't have coattails working for them. This year they gained 13 seats to take control of the New Jersey Assembly, and made a nearly successful run at a U.S. House seat in Texas' 1st district, a part of the rural South where Democrats hold every local office. GOPAC, headed by former Delaware Gov. Pete du Pont, has taken as its special task helping Republican legislative and local candidates in places where a U.S. House seat winnable by Republicans may open up in some future election.

Local factors inevitably differ: anti-tax feeling helped Republicans in Michigan, a strong right-to-life movement in Minnesota. But there does seem to be a common thread in these successes. These candidates talk of positive things government can do, not just of the need to cut back government. Their rhetoric is not airily abstract, but cheerfully practical. The Republicans, as a party that has been skeptical about government and politics, for years had a harder time than the Democrats finding candidates with natural apititudes for those subjects. Now, in different parts of the country that have long been Democratic, they seem to be coming up with more. They don't appear likely to get the ruling in the Indiana case that will overturn Democratic redistrictings elsewhere. But they may be on the road to winning control of more legislatures nonetheless.