NATIONAL ELECTIONS / TEXAS RUNOFF : Richards Beats Mattox in Battle of Democrats : She wins with 56% of the vote after a scrappy campaign on both sides. She’ll face Republican Clayton Williams Jr. in the fall governor’s race.

Ann Richards, the Texas state treasurer who gained national prominence with a sarcastic keynote attack on George Bush at the 1988 Democratic convention, scored a resounding victory over Atty. Gen. Jim Mattox in the state’s Democratic gubernatorial runoff election Tuesday.

With 90% of the precincts reporting, Richards had 571,742 votes, or 56.2%, to Mattox’s 445,403, or 43.8%.

The vote ended one of the nastiest campaigns in Texas history. Richards never trailed as the election results rolled in Tuesday night in her race against Mattox, whom she had called the “garbage politician of Texas.” She is the first woman to win the Democratic nomination since Miriam (Ma) Ferguson did so in 1932. Ferguson went on to win the governorship.

Richards will face Republican candidate Clayton Williams Jr., a political neophyte whose folksy cowboy-millionaire image swept him to victory in the April primary over his more experienced rivals.

Williams has said he would be more uncomfortable facing a woman and Republican strategists have said Richards could be a more formidable opponent than Mattox in the fall general election. Among other things, she will be able to take advantage of a Williams gaffe in which he said ugly weather was like a rape: “If it’s inevitable, just relax and enjoy it.” He later apologized.

In her victory speech, Richards told a group of supporters in Austin that it had “been a very long, hard race” that she compared to a demolition derby. At the same time, Mattox vowed to close ranks within the party and work to help Richards defeat Williams in the general election.

“My feelings about the principals of the Democratic Party are far deeper than my own ambitions,” he told Austin supporters.

Both Mattox and Richards had pledged to run a clean campaign, but the promise was hardly out of their mouths when the contest was reduced to a name-calling match virtually devoid of any discussion of issues.

Most vocal was Mattox, a man known to run no-holds-barred campaigns throughout his political career. He launched his attack early on, insinuating at first that Richards had been a user of illegal drugs 10 years ago before she underwent treatment for alcoholism. He ran television ads asking, but not answering, the question of whether she had used drugs and challenged Richards to produce her medical treatment records to prove that she was treated only for alcoholism.

Finally, in the closing days of the campaign, he accused Richards outright of having once been a cocaine addict. He also said he had affidavits from people who saw her use illegal drugs. Yet he never made the affidavits public.

For her part, Richards compared Mattox on the last day of the campaign to a “chicken-eating dog” who needed to be broken of his bad habits.

Among other things, she accused Mattox of hiding his true personal income and chided him for refusing to make public his income tax returns, as she had done. In television commercials, she pointed out that Mattox had been indicted in 1983 on bribery charges, but failed to mention that he had been acquitted.

She also called into question his receiving $200,000 in a land deal from a man now under indictment on racketeering charges. Like Mattox, she offered no proof that her opponent had actually done anything wrong.

The runoff followed a bitter three-way primary fight in which neither Richards nor Mattox gained a majority. Richards dealt a blow to former Gov. Mark White in the primary, accusing him of lining his pockets while in office. After being eliminated in the primary, White accused Richards of using Gestapo tactics.

The intensity of the campaign surprised even the most jaded observers of Texas politics, which has long been known as a place where political campaigns are bare-knuckle scraps. Pollster Richard Murray said he would have believed the usually tough Democratic primary would have moved in the direction of moderation in view of the fact that Republicans were gaining ground in what was once an essentially one party state.

“I guess the learning curve has flattened out,” he said. The intensity of the campaign was expected to weaken the party as it faced the general election battle.

George Christian, former White House press secretary and now a political consultant in Austin, called the Richards-Mattox battle the worst he had seen since the advent of television advertising and he said the news media was to blame, at least in part.

“The press was more apt to print unsubstantiated charges that were thrown around,” he said. “I think the press was used more by all the campaigns than I’ve ever seen it.”