Houston — When Ronald Reagan carried Texas in the last presidential campaign, it was his conservative ideology that made the difference with Lone Star state voters. But this year, it may well be his handling of the economy that determines whether Texans back Republicans at the polls.
Last November, Mr. Reagan's coattails swept aside Democrats while carrying Republican newcomers into office at all levels. But 1982 could be very different, according to campaign strategists in Texas.
The Sunbelt as a whole and energy-rich states such as Texas and Oklahoma in particular have, so far at least, been relatively free from recession. Political observers in Texas, however, say that candidates here are watching the recessionary front push south like a chilling cold front.
Problems in the frost belt have already led to scaled-back mining and drilling in the energy states due to the North's recession-pinched demand for steel, oil, and oil products.
Added to worries about the recession sweeping further south, Sunbelt politicians are still battling over serious congressional redistricting problems.
For instance, in Texas last week, the Justice Department ruled against the state's latest redistricting plans, charging that those plans may discriminate against blacks, Hispanics, and Republicans. Federal judges then stepped in reluctantly to postpone filing dates and attempt to draw up acceptable districts.
The Texas redistricting battle is adding heat to an already hot campaign for governor. The state's first Republican governor in over 100 years, William P. Clements Jr., faces a stiff challenge from Texas Attorney General Mark White, among other Democrats. Redistricting has become a central issue in this race. Mr. White charges that Governor Clements helped engineer ''a crass, blatantly political decision'' by the Justice Department.
President Reagan's ''new federalism'' initiative adds another layer of uncertainty to Sunbelt politics. Even Texas, with a healthy budget surplus, is dubious about taking over a wide range of federal programs in return for the federal government assuming all costs of medicaid and surrendering some excise tax revenues. Some politicians here estimate that the swap initially could cost the state at least an extra $130 million per year (although the White House disputes such estimates of increased costs for the states.)
Two Texas congressional campaign advisers - one working for a Democrat, the other for a Republican candidate - agree that the President's plan overall would probably benefit Southern and Western states at the expense of the North and East. They say the plan also fits with Texas' public support for cuts in federal government spending and power.
But the Democratic candidate's adviser argues that ''1982 is going to be a good year for Democrats. Just how good depends on the state of the economy; if the economy turns around in the next month or two and is, however slowly, climbing back up, then it won't be all that bad for Republicans.
But if the economy continues going down for two, three, four, five months, it could be a disastrous year for Republicans.''
In this view, the President's new federalism ''is really going to exacerbate regional antagonism in this country, with the states fighting each other for a bigger share of the apportionment and a smaller share of the costs.'' One cause of concern is that revenues produced by taxing oil produced in Texas-based industries accounts for one-third of the windfall profits tax which is earmarked for transfer to the states, claims this adviser. As a result, he says, ''Texas is going to wind up subsidizing state capitals all across the country, which is going to be resented by Texas.''
Add this resentment to the fact that no party holding the White House has gained a congressional seat in an off-year election since 1934, he says, and the result is that Democrats should regain ground lost to the Republicans in 1980.
The view among some Republican advisers here, however, is that Republicans are well placed to gain more ground.These gains will come, they say, from having learned to talk the South's traditionally conservative Democrats into changing their votes if not their party label.
Key to the Texas vote, one Republican explained, is the fact that ''Houston doesn't know that there is a recession and Texas as a whole is only mildly aware of one. . . .''
Voters from Georgia to California, he says, are breaking old patterns because ''the mood of the people is conservative or Reagan-oriented, with a growing emphasis on policies rather than on traditional party labels.''