Sometimes in this part of East Texas the winds of change can be just a gentle breeze. Take the case of the Harrison County League of Women Voters' candidates forum here, the last held before First Congressional District voters voted on a new congressman in last Saturday's special election. Presiding at the forum was the local league president, Dave Snow, the second member of his gender to hold that office.

But whether the winds of political change are gusting in the direction of party realignment and Republican control of the socially conservative Sun Belt now will not be known until the runoff House election between Saturday's first-place finisher, Republican Edd Hargett, and the top Democrat, Jim Chapman, is held in five weeks. Suddenly the stakes in Texas are big for both parties.

an Hargett had a war chest of $650,000 and some of the national party's top media and polling consultants to advise him on how to deploy it. But populism and xenophobia both have deep roots in East Texas; "outside" money and support, especially from Washington and the despised East, could become issues against Hargett.

Party Factor. The day before the primary, a leading Republican strategist expressed concern that a runoff election would "become much more of a Democrat-vs.-Republican thing," a development presumably of little benefit to the GOP in a district that has sent only Democrats to Congress for more than a century. Less than 48 hours after the polls had closed, both parties appeared eager to recycle campaign themes that had worked for each before in the South. Democrats seek to "localize" the contest ("Remember you were rocked in a Baptist cradle by a Democratic hand.") while Republicans would prefer to "nationalize" the race (Do you want a congressman who will vote with President Reagan or with Walter Mondale and Tip O'Neill?)

Social Conservatism. The candidate campaigning against the "loopholes that let some big corporations and rich people avoid paying their fair share" was Republican Hargett, who emphasized his commitment to both Social Security and Medicare to the voters of the oldest district in the state. Economic populism still sells in East Texas. But in matters of social conservatism, Texas Republicans have emphatically dominated the debate. Hargett does not appear uncomfortable with his state party's official position that defines homosexualtiy as "an abomination before God, perversion of the natural law . . . indicative of a society's moral decadence."

There are no Republican yuppies in the First District of Texas. Yuppies, who are social libertarians and economic conservatives, left home towns such as Marshall and Texarkana to move to more permissive big cities such as Atlanta, Houston and New Orleans. Keeping rural social conservatives who are economic populists harmoniously in the same party with conservatives who are socially laissez- faire will require exceptional skill.

The Democrats. If Democrat Jim Chapman loses, Republicans will have an easier time recruiting House candidates to challenge incumbent Democrats throughout the rural Sun Belt. A Hargett victory may convince some House Republicans that their party could control Congress by 1992 by winning conservative southern districts where the electorate is Democratic by tradition rather than by conviction.

But perhaps most serious of all for the Democrats is the bad news from the polling data in the First District race: the younger the voter, the more likely he or she is to be a Republican. Republicans are hoping to move into their own home in the First District; Democrats are hoping not to move into the nursing home. That may help explain why the one issue that obviously worked for the Democrats in the primary election was preserving Social Security. It was about all the Democrats had going for them in a district where Ronald Reagan has a favorable rating of 3 to 1. In five weeks East Texas could tell us whether realignment will be postponed once more.