In the age of plastic candidates, tape-recorded philosophy and campaign by television, it may be inevitable that electoral politics smiles, but wanly on its Bob Eckhardts.

After 14 years as one of Houston's men in the House, leading almost always with his chin, Rep. Bob Eckhardt [D-Tex,] went down in the Republican tidal wave Nov. 4.

Eckhardt, 67, is one of those southern originals -- one of the last of the House's consumer champions; one off the last members willing to stand toe-to-toe against Big Oil, even though he came from its home town; one of those lawyers who could dispatch a bad bill with one idea and a dozen words of logic.

An original, too, in appearance. He wore floppy bow ties, vests and a wide-brimmed hat that made him look the prototypical planter. Except he wore that get-up astride his bicycle. A Texas drawl four yards long nicely disguised an agile mind and a streak of goodness that reached from here to the horizon.

And Eckhardt managed to find fun in the legislative drudgery. When pomposity and greed prowled the House floor and committee rooms, Eckhardt limned it all with a felt pen. He unendingly doodled professional-quality caricatures reminiscent of old Vanity Fair and Thomas Nast renderings.

He lost by about 4,000 votes last month to Jack Fields, a young lawyer who had never held public office. Fields, it is estimated, spent on the order of $700,000; Eckhardt, about $290,000 in their costly race.

The pundits and seers have their theories for these things but one need look no further than Eckhardt's race in Houston to see what's happening generally to electoral politics. Big money and emotion are increasingly forceful.

In the last three congressional elections, oil and gas interests spent an estimated $1 million -- and maybe more -- trying to end the House career of Eckhardt, who refused to change his ways.

Some legislative sins are forgiven, but Eckhardt's was not. He sired the language in 1975 that kept price controls on oil. Eckhardt figured that saved consumers $63.8 billion, and the industry was unforginig.

In 1976 and 1978, the oil and gas lobby tried to unseat him but failed. With help from other and new elements in the political mix, in 1980 Eckhardt became another of the Democratic liberals who bit the dust.

An Eckhardt staff study found that roughly 57 percent of Fields' money came from organizations and individuals connected with oil, gas and utilities.

"Over those three elections, they kept on spending and the oil companies spent over $1 million to defeat me," Eckhardt said one recent afternoon. "But my opponent didn't run on an oil issue. They used an extremist approach, in which every prejudice was played on . . . Groups like Moral Majority and the National Rifle Association don't raise the money. They afford the emotional issues and the oil interest put up the money."

Eckhardt's record on such things as consumerism, auto safety, environmental protection, toxic substance control didn't stir much excitement. He was hammered repeatedly on busing, school prayer and gun control, issues almost impossible to deal with in 30-second TV responses.

As a Texas liberal-populist -- a sort of political snail darter -- with 22 endangered years in state and federal elective office, Eckhardt could see last November coming, and had pretty much reconciled himself to its inevitability.

"The probability of losing is pretty high unless one operates in a way that is designed to constantly stay in office. I was more concerned with the process than in staying here, and I was not willing to devote all my time to keeping this job," he said. Concern with process kept Eckhardt here during September when he might have been better off campaigning before the October recess. He was working to modify railroad deregulation legislation and assure continued rail service to his area.

"I believed Edmund Burke's idea that a legislator should not simply be a reflection of public opinion.I don't want to be a little Univac machine, but we are moving more and more in that direction and we are getting a kind of professional representative who does not necessarily afford any impact on the legislative body as an intellectual personality," he said.

Around the House and Senate, Eckhardt was recognized as an intellectual personality who made an impact. Some who appreciated that may have taken his defeat harder than Eckhardt did.

Rep. Henry Gonzalez (D-Tex.), for one, was heartsick. "It was sinful for Bob to lose like that. He's independent and we're losing that around here.He is sedate, scholarly and serious -- the kind of legislator this country cries for," Gonzalez said.

"He was a seminal thinker in the legislative process. He was devoted to the greatest good for the greatest number. But in Texas he was considered not only independent, which was bad enough, but as betraying people on oil pricing. That was a dastardly act in the book of Big Oil," he added.

Ironically, after his 1975 action, Eckhardt came back the next year with legislative help for small oil producers, but didn't get much thanks for it. "It's never enough for these folks," he said.

By 1978 he was antagonizing them again with efforts to slow the rush to decontrol natural gas prices. His reason then, as in 1975, had more to do with national economics than antipathy toward the oil barons.

We were moving rapidly into recession and we had a mounting inflationary process. It was the same as early 1979. I just felt it was a major economic issue and it was important to prevent too great peaks and nodes in prices," Eckhardt said.

Throughout that period, Eckhardt's quarterly reports to constituents, scholarly documents with complicated graphs and tables, make clear that U.S. petroleum policies were as much at fault as the lords of OPEC in creating economic problems.

Somehow, the message never took.

So when the 97th Congress opens next month, Bob Eckhardt won't be a part of it. He plans to teach, do some writing, perhaps join a Washington law firm and keep raising his logical kind of hell.

"A lot of little things contributed to my defeat and a lot of it was my own fault," he said. "But it would have been an anticlimax for me to remain in Congress . . . I think I can do more now outside Congress than in it. It's a new, open vista for me. And, you know, Congress has a helluva lot of dull stuff going on."

Depends on the perspective. It never seemed dull with Eckhardt around.