Twenty-five years after Ralph Nader made himself a household word with "Unsafe at Any Speed" -- a devastating expose of the dangers of General Motors' sporty Corvair -- the famous consumer advocate is still controversial. He is "Saint Ralph" to some, a devil and fanatic to others.

In an interview with Nader at his headquarters here, I found him untroubled by his critics but somewhat frustrated. He says it's tougher to get press coverage than it was 25 years ago. And without press coverage, Nader complains, it's almost impossible to get congressional action.

After the success of "Unsafe at Any Speed," his crusades were widely covered by the three newspapers and three networks he considers crucial to his cause: The Washington Post, New York Times, Wall Street Journal and ABC, NBC, and CBS. "I know all about CNN {Cable News Network}, and the independent stations, and the fine regional papers -- but if {the consumer issue} doesn't get covered in one of those six, especially in those three papers, it's gone," Nader said.

There was a turning point in press and congressional reaction in the early 1980s, coinciding with the Reagan administration's rejection of consumerism, which had blossomed under Jimmy Carter and even under Richard Nixon.

Ronald Reagan accelerated the process of deregulation that had begun late in the Carter years. As the business community encountered economic problems, or lost out in competitive situations to Japan, "it began to use overregulation as the excuse," Nader said.

Moreover, the Reagan administration failed to apply statutes on the books, such as the antitrust laws: "When nothing's happening, that's not considered news. But I tell reporters that when nothing's happening, that's news. Reagan fell into a wonderful vacuum with the press: as long as nothing was happening in the Environmental Protection Agency, for example (except a little corruption), there was no news. But for six straight years, there was nothing doing on {contaminated} drinking water, when the act is clear as can be."

Around the same time, the papers "began suburban sections and adopted a 'be-nice-to-business' philosophy and that had an unbelievable effect on Congress. Committee chairmen don't hold hearings to talk to themselves. They only hold hearings if they can be promised coverage." The papers now run "nice safe, consumer stuff, 'consumer news you can use,' you know, how you can save money at the supermarket," Nader snickers.

Nader blames his decline in popularity among the media on "a massive corporate counterattack that started with the creation of the Business Roundtable in 1971. Then there are the right-wing think tanks that began to be funded -- American Enterprise Institute, the Heritage Foundation . . . and so on."

Nader's critics choose from a broad menu. Some criticize his austere personal life style (as if it were relevant); his drive, as they see it, for excessive regulation or reregulation of the United States economy; and, lately, his encouragement of class-action suits that wind up, says former Reagan administration official Ken Adelman, in -- "everyone . . . suing everyone else." Still others regard Nader as a bore, ready to put "warning labels on every French fry."

Last month, a highly critical Forbes Magazine cover story suggested that Nader is too cozy with lawyers who provide funding for his many consumer groups. This piece synthesized much of the accumulated business-establishment bitterness against Nader, warning that he would be back with a vengeance in the 1990s after slipping out of favor in the 1980s.

Forbes' editors thought it wise to say affirmatively in the final paragraph that they had not concluded Nader "is corrupt." Instead, the magazine said, he is paranoid, suffused with a sense of moral righteousness, "unsaintly -- and untrustworthy -- at any speed."

Nader, nonetheless, is pursuing an elaborate new agenda that ensures he will remain as controversial as ever. Given the current weakness of financial institutions, the reader can be sure that Nader and his various satellite organizations will continue to nag at the public consciousness in the '90s.

He is also exporting his message. Nader just returned from visits to Eastern Europe and the Soviet Union, where fledgling consumer groups are trying to establish Nader clone-organizations. He is also active in Japan, a society even more industry-oriented than our own.

Nader's ideas about the need for greater business and industrial responsibility to the consumer, which some argued 10 to 20 years ago were too radical, are now generally accepted as prudent around the world. In my book, he is no more radical than was Franklin D. Roosevelt. Both had detractors, but both set out merely to save the American system by making it live up to its own stated ideals. "Nader blames his decline in popularity among the media on 'a massive corporate counterattack . . .' "