Senate Majority Leader Robert Dole claimed he'd been invited to the Pamela Harriman love-in last night "because they wanted some Republican to show up, but they told me not to wear a tux so I could stand out from the others." But he said, plaintively, "I've never had a chance to talk to Mrs. Harriman about fund raising. I'd like to talk to her about 1988."

Dole was speaking at "A Tribute to Mrs. W. Averell Harriman" at the Sheraton-Washington Hotel during a fundraiser for the National Mental Health Association hosted by Mark Russell. The evening raised $100,000 from the sale of the 600-or-so tickets at $200 a person and up to $5,000 a table.

Dole added a series of off-the-cuff one-liners: "I'm sorry the president couldn't be here today, but he wasn't invited. George Bush is a nice man. I look forward to meeting him sometime. We're putting in a tax deduction for Jack Kemp's hair spray -- $5,000 a year. Now I want to say a word about the purpose of the evening -- but I brought the wrong paper."

Dole finally got around to praising Harriman for her philanthropy and for the bipartisan efforts for mental health.

Though Harriman has long been associated with efforts for mental health, her other reputation as a political fundraiser brought out a great crowd of hallowed Democratic names -- led by her husband, Averell Harriman, 94, making what was billed as his first public appearance in three years.

Lawyer Clark Clifford, defense secretary under Lyndon Johnson, said Harriman had learned an early lesson about Washington: "Half the people in town are waiting to be discovered, the other half are afraid they will be."

Former first lady Lady Bird Johnson, in a flowered dress, said she was lobbying with her son-in-law, Virginia Gov. Charles Robb, to have wildflowers planted along Virginia roads.

Luther Hodges Jr., a Carter Commerce Department official who is now head of the National Bank of Washington, was cochairman of the dinner with his wife Cheray.

Rep. Claude Pepper received congratulations on his recent 85th birthday. "Just a little birthday," he said.

New York Gov. Mario Cuomo, representing the new Democratic lights, made it to the VIP reception, where he said he thought President Reagan's tax bill was "a help to the poor, too good to the rich, but bad for the middle-income people." Although scheduled to give a tribute to Harriman, Cuomo left early after an urgent telephone call.

House Majority Leader Jim Wright (D-Tex.) spoke, extemporaneously, in Cuomo's stead, praising Harriman and throwing in a tribute to Lady Bird Johnson, saying that when he sees the banks of flowers in the capital, "I know Lady Bird has been here."

Kitty Carlisle Hart, the singer and actress, described by Harriman as her very best friend, sang her tribute, "I'll Be Loving You Always." At the reception, she said her own interest in mental health went back to her husband Moss Hart, who "was the first to write a musical about psychoanalysis, 'Lady in the Dark.' "

Pamela Harriman, in the receiving line before the dinner, said she had been interested in mental health long before she married Averell Harriman, whose mother was an early pioneer in the field. In accepting the tribute at the dinner, Harriman seemed to bring together her interests in mental health and politics when she said the challenge of mental health "demands the generosity of the private sector -- and it deserves a priority in the public agenda. And I believe the day is coming -- and coming soon -- when America will move decisively in the direction of justice and renewed concern.