FOR A QUARTER of a century in the halls of Congress, there was one big man among lobbyists--in size as well as ability to influence the lawmakers and their laws. And when asked what it was about his approach that worked so well, Andrew J. Biemiller--the voice of organized labor in America --would quote his boss and close friend, George Meany: "George told me to remember just three things: don't beg, don't threaten and don't think you are always 100 percent right." Mr. Biemiller, who died last Saturday at the age of 75, was faithful enough to this advice to become perhaps the single most influential lobbyist in town.

And if the influence of the labor movement had begun to wane by the time Mr. Biemiller retired as director of the AFL-CIO department of legislation, his impact on civil rights and social welfare legislation would endure. Early on, as a congressman from Wisconsin, Mr. Biemiller was Hubert Humphrey's principal ally during the 1948 Democratic convention platform committee fight over a civil rights plank. As labor's legislative expert, Mr. Biemiller also joined with civil rights groups to buck Kennedy administration opposition and write a fair-employment-practices clause into the civil rights bill that was enacted in 1964.

There was Mr. Biemiller's longer and less successful effort for national health insurance, which he began as a member of the Wisconsin legislature in 1937 and never stopped pushing. "I guess that's my biggest disappointment," he said upon retirement, "the utter lack of anything on health insurance after Medicare."

Congress kept changing, though, with "more and more of the people up there . . . concerned about their own district and about nothing else," Mr. Biemiller noted when he finally left the Hill. "They don't listen to the leadership . . . . There isn't much fun up there anymore." Be that as it may, the fun-- and the serious legislative business of forging civil rights, health care and worker protections--was richer for the gregariously gruff, slightly rumpled, knowledgeable and respected presence of Andy Biemiller, when and where it counted.