Rep. Henry Waxman (D-Calif.), a small soft-spoken man with a thick mustache and a shy smile, looks like a milquetoast or one of Charlie Chaplin's characters bumbling through a baffling world.

He is anything but that. The House of Representatives found that out last week when Waxman knocked off a respected veteran backed by the leadership, Rep. Richardson Preyer (D-N.C.), in a bruising battle for the House Commerce health subcommittee chairmanship.

In southern California Waxman already was known as a tough political operator. With money contributed from wealthy Beverly Hills movie stars and affluent Jews, he has formed a sophisticated successor to the old political machine, and has used it to help elect like-minded liberals to state and national office.

Waxman brought the same political intensity to his chairmanship race. He called on environmental groups and Ralph Nader for help.

The United Auto Workers, and Sen. Edward M. Kennedy (D-Mass.), who expect him to favor their push for a more comprehensive national health insurance program, also pitched in, and two of California's political heavyweights, Senate Majority Whip Alan Cranston and Rep. Phillip Burton, came to his aid.

Waxman also set up a political action committee funded by his wealthy California contributors and distributed about $40,000 to 30 of his liberal Democratic colleagues, including eight who served on the Commerce Committee. Seven of those recipients on Commerce voted for Waxman. The donations also brought Waxman considerable criticism.

His victory may affect not only the future of national health insurance, clean-air legislation and other issues under his domain, but it also has implications for the entire House.

Waxman belongs to the hard-charging, post-Watergate Democratic class of 1974 that might be called the "wewon't-wait" generation.

His victory came when there was a feeling on Capitol Hill that further assaults on the seniority system wouldn't be successful.

Waxman's race pushed that fight over seniority to the subcommittee level -- where much of the important action on legislation now takes place.

Also last week, one of Waxman's cohorts, Rep. Toby Moffett (D-Conn.), captured the chairmanship of a key energy subcommittee on the Government Operations Committee -- a victory that shocked more senior members.

Waxman, Moffett and Rep. Andrew Maguire (D-N.J.) also helped Rep. Bob Eckhardt (D-Tex.) defeat the more senior Rep. John Murphy (D-N.Y.) for the chairmanship of the Commerce oversight subcommittee after extracting promises from Eckhardt that he would consult with the younger members on his agenda and would be as aggressive on oversight as Rep. John E. Moss (D-Calif.) had been before he retired.

Those events have greatly disturbed House leaders.

Moffett and Maguire belong to a group of liberals in "The Gang That Couldn't Shoot Straight."

The group had a reputation of talking rather than organizing and its moves rarely got anywhere. Now there is some fear that under Waxman's tutelage the "gang" is getting politically smart.

House leaders were upset by Waxman's victory because they believe the seniority system is still a valid means of moving members into chairmanships.

They contend that a senior member should not be knocked off unless he or she is autocratic or incompetent or has some other gross deficiency. Preyer, they point out, was a moderate with a reputation for integrity.

They fear, particularly because of Waxman's use of money and outside interest groups, that chairmanships will be put on the block subject to the pressures of campaign funds and special interests.

"It was just a very bad precedent for a guy to go around giving money to his colleagues on the committee when he was involved in a chairmanship race," a leadership aide said.

Waxman sees nothing wrong with distributing money. "What's wrong with a man helping out his colleagues?" he asked.

As for the seniority issue, he said, "I think it's a healthy thing to have a contest for chairmanships."

Waxman first won public office by defeating a 26-year veteran for the California Assembly after dozens of other young lawyers decided not to enter the race.

Since then, Waxman and assembly Majority Leader Howard Berman have put together what is known in California as "the Waxman-Berman machine." Their most recent success was to back Rep. Julian Dixon (D-Calif.) over three other candidates in a primary to fill Rep. Yvonne B. Burke's (D-Calif.) seat.

As a California Journal article said of Waxman: "Waxman... entered politics with a firm grasp of two simple theories: two votes are more than twice as good as one if they stick together, and God never meant liberals to be stupid."