He talks about drift fishing for northern pike in Gull Lake back home in Minnesota in the summertime. Skiing on barrel staves when he was a boy in Minneapolis. Toboganning with his children. He talks about religion. Family life is disintegrating in the United States, he says, and maybe the country will go the way of the Roman Empire. He talks about the time he admitted to college authorities that he had shot a game of pool and they suspended him for a few days.

The remarkably blue and friendly eyes of Luther W. Youngdahl, 81, senior judge of the United States District Court for the District of Columbia suddenly him turn icy.

Now he is talking about corruption. He would like to know, he says, why the state of Maryland seems to have such problems.

"Not once - not during the three terms that I was governor of Minnesota - did anyone ever approach me to ask a favor, not about a contract or anything else," he says. 'Of course, they knew they would have been thrown down to the bottom of the steps of the capitol if they had tried."

Gov. Youngdahl was a racket-buster. He drove the slot machines out of Minnesota. Some of them wound up in South Dakota. He barks a high laugh, but his eyes remain cold.

Now he is recalling the late Sen. Joseph R. McCarthy (R-Wis.) and the assaults on constitutional liberties that were made in the name of his crusade against communism. Judge Youngdahl turned back one of those assaults in one of the celebrated cases of that time. He remembers the hate mail that came as well as the congratulations.

"I'm prouder of that case than anything I ever did legally," youngdahl says. "McCarthy, Even to mention the word 'Communist' was a terrible thing. It was the toughest case I ever had."

He sits erect in the living room of his apartment on Cathedral Avenue in northwest Washington. His hair is full and white - it really is a mane and his thin nose curves out and down like the beak of an eagle. His eyes become merry again as he remembers what he did.

The case was that of Owen J. Lattimore, a former trustee of the Institute of Pacific Relations and editor of its magazine, "Pacific Affairs," and later a professor at Johns Hopkins University. In 1950, McCarthy alleged that Lattimore had used his influence at the institute to promote ideas favorable to communism. Moreover, he said that Lattimore was "the top Russian spy" in the United States.

Lattimore subsequently testified before a Senate panel in lengthy and acrimonious hearings. He was accused of lying to the Senate, charged with perjury, and went before judge Youngdahl for trial.

Youngdahl dismissed the charges on the ground that they were unconstitutionally vague.

The charges, he wrote, "demonstrate that the government seeks to establish that at some time, in some way, in some places, in all his vast writings over a 15-year period, Lattimore agreed with something it calls and personally defines as following the Communist line and promoting Communist interests . . . To require (Lattimore) to go to trial on perjury charges so formless and obscure as those before the court would be unprecedented and would make a sham of the 6th Amendment and the federal rule requiring specificity of charges."

Whereupon Leo A. Rover, the U.S. attorney at the time and the man in charge of the prosecution, filed an affidavit asking that Youngdahl excuse himself from continuing in the case.

"I've never been so insulted in all my life," Youngdahl says as he recalls the incident. "Before I went on the bench, I folded my hands and said a little prayer. I didn't ask any questions, I just let him talk . . . The meaning of communism I asked him what he meant by that, and he said he'd go gome and look it up in the dictionary."

He laughs his high laugh at the absurdity of it. He gives a visitor to understand that that is all that is necessary to say about that, and he turns to his wife, Irene.

"I proposed to her in a rowboat on a lake outside Gustavus Adolphus College in Saint Peter, Minn.," he says. "I made sure she couldn't swim, because if she'd said 'no' I was going to throw her overboard.But she said 'yes' and now I've got a beautiful woman and a good cook."

They were married on June 23, 1923. (They have three children and 10 grandchildren.) Youngdahl had just lawyer. In 1930, he became a municipal judge in Minneapolis, then, in 1936, a county judge. From 1942 to 1946, he was a member of the Minnesota Supreme Court. In 1947, he began the first of his three, two-year terms as governor of the state.

As Youngdahl, who describes himself as a liberal Republican, was finishing his last term as governor, Hubert H. Humphrey, the redoubtable Democrat, was preparing to run for re-election to the U.S. Senate. There was some talk that the popular Youngdahl would run against him.

"Actually, I was fed up with competitive politics," Youngdahl says. "I wanted to end my life in the federal judiciary. I wanted to be a trial judge. I never liked appellate work."

So Humphrey arranged a meeting between Youngdahl and President Harry S. Truman, and Truman appointed him to the federal bench here. In 1966, at the age of 70, he took senior judge status, meaning that he still sits part-time.

On Oct. 20, the 23 persons who have served as Youngdahl's law clerks since he became a judge here presented him a portrait of himself. It hangs now in the Ceremonial Courtroom of the U.S. Courthouse.

"If I had to write my ticket all over again, I wouldn't write it differently," the judge said recently. "Now life is getting even happier. Dealing with human problems. Being able to work half-time. It's really a wonderful privilege. Age is not a matter of arithmetic; it's the state of your mind and your outlook, the companion you have."

Irene was sitting on the arm of the judge's chair.