Washington — The senator widely regarded as one of the funniest men in Washington was at it again. Alan Simpson (R) of Wyoming was apologizing to reporters for being 10 minutes late for a breakfast session. He said that he had run right smack into a traffic jam, occasioned by a sudden downpour.
''The traffic,'' he said, ''is not as heavy in Wyoming. There's a great story there. This Eastern lady, visiting Wyoming, walked up to the guy standing by a fence post and she says, 'I understand you have more cows than you do people out here. Why is that?' He looked at her with steely gaze, hooked his finger in his belt, and he said: 'We prefer 'em.' ''
A longstanding but unanswered question in the world of politics is whether wit and humor are assets for a political candidate.
This year's crop of Democratic presidential candidates doesn't include any really funny people - no Adlai Stevenson, no Eugene McCarthy, no Morris Udall.
Walter Mondale can banter with the best of them. But he's not known for being funny. Sen. John Glenn (D) of Ohio proved he could get laughs, given a good script, at the recent Washington Gridiron Club journalists' banquet. But Senator Glenn is not really funny.
Sen. Gary Hart (D) of Colorado is good humored. Sen. Alan Cranston (D) of California has a little dry humor. So does Reuben Askew. Of them all, Sen. Ernest Hollings (D) of South Carolina is best at the spontaneous quip. And he will sometimes say quite outrageous things just for the shock and the laugh that follows. But Senator Hollings isn't known for keeping audiences in stitches.
Then, of course, there's President Reagan, the great communicator and, also, the great entertainer. No one in public life is better with a quip. But Mr. Reagan applies his wit judiciously, and thus has escaped being cataloged as a funny fellow. If having humor in a politician's arsenal is an asset, Mr. Reagan knows how to make the most of it - and he would be likely to out-quip his possible adversaries in 1984.
Sometimes, though, being funny is a liability. The sophisticated wit of Adlai Stevenson aided his quick rise to national prominence as the Democratic presidential nominee in 1952. But he overdid the witticisms. Before the campaign was over, his tendency to make light of things was turning away a sizable portion of voters. Eugene McCarthy, a waspishly witty man, may have been the funniest politician ever to hit the political circuit. But before long it became clear that many people were coming to laugh at his witticisms - and not to listen to his serious thoughts.
At one point, in his first bid for the Senate, McCarthy toned down his humor - and, at least so it seems, he has never fully unleashed his humorous talents since. McCarthy did, however, recently get some laughs with his comment that most of the Democratic presidential candidates are actually running as someone else: Walter Mondale, he said, ''really wants to be Hubert Humphrey,'' and Sen. Gary Hart is ''a composite of all the Kennedys.''
Asked if he had ever been ''hurt politically'' by his use of humor, Senator Simpson said: ''There's a difference between being a humorous fellow and being one who is kind of the professional master of ceremonies. I've always carefully guarded myself from being the professional master of ceremonies. And I can do that - being an MC - and I think I do it rather well.
''But there's another kind of humor. There's the ascerbic, slashing, personal , make-fun-of-somebody-else kind of humor that is big stuff around here. You take another human being and say something awfully funny. And then you get a laugh. But down inside a sensitive person the response is: 'Gee, he really didn't have to do that.' Or 'she didn't really have to do that.' I've never played with that kind of humor - ever.''