Fred Meyer is a string bean with a shock of red hair, a perpetual motion man who climbs mountains and runs marathons and quotes from Plato and Camus and laughs at himself when he says, "It doesn't take a genius to see when you're on a roll."

He labors in relative obscurity in the world of politics, a lowly Republican county chairman who still believes in organization and the power of ideas in an age of broken-down parties, mediagenic candidates and independent voters.

But though little known in national circles, Fred Meyer is presiding over a historically significant turnabout in political power here. It may put to rest the old axiom that the Republican Party is incapable of capturing control of the county courthouses in the South and Southwest. The same thing has begun to happen in Houston.

Since his election as county chairman in 1979, Meyer and startled Democrats have watched a remarkable procession of Democratic elected officials and party activists into the Republican Party. At least 18 incumbents have changed parties, and Meyer's effort to take over the courthouse reached its peak this month when the Democratic Party failed to field candidates for nearly half the 59 county judgeships that will be contested next November.

The Republicans, in contrast, filed a complete slate and seem assured of a majority of the nearly 70 county judgeships for the first time since Reconstruction.

In addition, Meyer has made overtures to the minority community here that may result in a new minority-dominated congressional district and has left the Democratic Party's relationship with many Dallas blacks in an uproar.

Democrats have cried foul, claiming that Meyer intimidated Democratic judges into switching by threatening to run candidates against them, but he calmly denies it.

"I made it clear we would welcome any of them who wanted to file," he says. "I made no secret of the fact that we were going to try to win those seats.

"The problem with the Democrats is they're still playing the same old tune," he says. "Having been down my entire life, having been in exactly the position the Democrats are now, they don't have anything to do but scream. They have no program, no direction except one that a majority of the people recognize as bankrupt."

Now Meyer believes the Republicans are in a position to sweep nearly every county office in next fall's election, including the top administrative job and a majority of the governing body, the commissioners court.

This is a stunning transformation in a county that has often voted for Republican presidential candidates, but as recently as 1977 had just one local GOP judgeship.

Meyer plays down his role, pointing to the steady increase in GOP votes in recent local elections. He also credits three other factors that made it easier to attract Democrats into his party.

Former governor John B. Connally's defection to the Republican Party nearly a decade ago. "At the time, it wasn't socially acceptable to be a Republican," Meyer says. "About the only good old boy willing to identify with the party was Connally."

Bill Clements' surprising victory in the 1978 gubernatorial race. "Now if you were young, you could see an alternative," Meyer adds.

Finally, "Texans could not identify with Jerry Brown or Ted Kennedy or, by the end of his term, Jimmy Carter. They couldn't see anyone in the national party they could identify with."

Like many southern states, Texas has long been controlled by Democrats, with bitter fights between the conservative and progressive wings. In most statewide contests, the conservatives prevailed.

In the Dallas area, the small Republican Party was identified with the city's affluent north side and with right-wing extremists. Almost 30 years ago, it appeared the county might shift to the Republicans when voters sent Bruce Alger to Congress and President Eisenhower was attracting hordes of conservative Democratic votes.

But the 1960 and 1964 elections, with native son Lyndon Johnson on the national ticket, interrupted that transition. Only recently has the Republican Party been able to persuade conservative Democrats that they could find happiness in another party.

But even disgruntled Democrats acknowledge that Meyer has made a difference. "If you've got two people on a street corner," said one party activist, "Fred Meyer will make it three. He's everywhere."

A longtime Republican activist calls Meyer the best county chairman in the modern history of Dallas.

Fred Meyer, 51, grew up in Illinois and says he was "pushing cards for my dad" in local elections when he was 8 or 9. He got an engineering degree from Purdue and later an MBA from Harvard, a badge he displays proudly.

He came to Dallas in 1967 to work for Tyler Corp., a conglomerate, and is now executive vice president and chief operating officer. In 1972, he met Alan Steelman and agreed to manage Steelman's successful campaign for Congress. Four years later, he ran Steelman's unsuccessful bid to unseat Democratic Sen. Lloyd Bentsen.

In late 1979 he was elected county chairman, and almost immediately things began to happen. That December, 21 active or former Democratic precinct chairmen and other activists switched parties. Ultimately, two Democratic county chairman jumped ship.

In the spring of 1980, Meyer invested $10,000 to $15,000 in radio ads on local country-music stations urging voters to "join your neighbors" in the Republican primary.

"We had to get away from the north Dallas image," Meyer says. The ads helped produce a larger turnout in the Republican primary than the Democratic primary.

Then, in the fall elections with Reagan sweeping the county, Republicans elected 11 of 13 contested county judgeships. Immediately afterwards, Meyer wrote to other incumbent Democrats making them welcome. A few at a time came to talk to him, and in groups they began to switch parties.

Survival was an important reason. "There were loads of A-Number-1 judges who got beat in 1980," says Judge Snowden Leftwich Jr., who recently jumped to the Republicans.

After the 1980 election, Meyer began computerizing the local Republican organization, which proved especially useful in the bitter fight over redistricting. Meyer recognized that the Democrats were reluctant to carve out a new Dallas district for minorities because it would threaten two of their incumbent congressmen, Jim Mattox and Martin Frost, and he set about to take advantage of their dilemma.

He drew maps that showed how such a black-Hispanic district could look and took it to a group calling itself the Coalition for Minority Representation.

"I said, 'Don't kid yourselves. There are two of us being had by the current arrangement, thee and me,' " Meyer says.

Meyer's initiative resulted in a new minority district with Frost as the incumbent. It also turned Mattox's neighboring district into a potential GOP stronghold.

Although considered a brilliant political stroke that won the admiration of some of the Dallas black community, the plan was rejected by a panel of federal judges. Frost's 24th district reverted to a majority white district, while Mattox's 5th district turned back into a Democratic stronghold.

But Meyer didn't give up there and now hopes for an even more stunning victory. On March 12, Lucy Patterson, a popular former Dallas city councilwoman who is black, announced she would run against Frost as a Republican.

Patterson, a lifelong Democrat who fought for a minority congressional district in the Dallas area, blasted the Democrats in her announcement for supporting the Voting Rights Act in Washington but undermining it back home.

If Meyer can persuade the Republicans in the 24th district, who make up about 60 percent of the white vote, to stick with Patterson, and if Patterson can split the normally Democratic minority vote with Frost, she could become the rarest of birds in Congress, a black woman Republican.

Meyer is confident that, regardless of the outcome of the 24th district election this fall, his courtship of the black community will pay off. "I'm working on a long-term basis," he says. "I'm ready to pay a price in the next election for the long term."

Fred Meyer has accomplished all this without the power once common to county chairman. He has no patronage, no huge staff and he recognizes the growing independence of most voters. He relies on hustle and enthusiasm.

"I'm a seven-day-a-week individual, 24 hours a day," he says. "To me nothing is worse than having a Sunday afternoon with nothing to do."