"Timing is everything," said Gerald Lowrie, AT&T senior vice president, at Ford's Theatre's 20th-anniversary gala last night. And for the opening of Sinclair Lewis' "Elmer Gantry," a musical about both the Depression and evangelists, the time was right.

Those two subjects were up to the minute for the full house of Cabinet and congressional figures plus corporate supporters, and they missed none of the nuances.

Former Virginia governor Chuck Robb joked that his wife had warned him before they came "to be circumspect in what I said" about evangelists, "because of the two we have in Virginia."

Lynda Bird Robb said that despite rumors, she's not running for Congress. "Our daughter Jennifer is still at home. And I'm on the National Commission on Infant Mortality."

House Speaker Jim Wright, there with his wife, Ford's trustee Betty, shook hands up and down the aisle as though it were a tent meeting. As for the Reagan budget, received by Congress yesterday, he said, "Interesting. Though I haven't read it yet."

Stewart Udall, who as interior secretary in 1967 supported Executive Producer Frankie Hewitt's idea to restore Ford's not just as a museum but as a living theater, came to receive a silver medal from Hewitt for his efforts. He pointed out that his "generation found a cultural backwater when we came to Washington 33 years ago." Now, he said, Ford's is an emblem "of what our generation has done for the arts. It's taken courage and foresight. And lots of corporate sponsors."

Udall told friends at intermission that he still lives in Arizona, "where I practice law and work for Robert Redford -- on his environmental projects." He's also writing two books: "I'm updating my book 'The Quiet Crisis,' on environmental issues, and another, well, about things in my own life."

Rep. Bill Frenzel (R-Minn.), his wife Ruthy and Rep. Bob Carr (D-Mich.), head of the Congressional Arts Caucus, were in the front rows, near Commerce Secretary William Verity and Energy Secretary John S. Herrington. Garfinckels and Raleighs owner Neil Fox came with fashion director Aniko Gaal, whose arms were encircled with big golden bracelets.

Lowrie said AT&T's OnStage program of funding for regional theater supported "Gantry" because "we encourage new and bold theater. We take risks with the arts." As for himself, he said the musical's plot seemed familiar to him. "I come from a town where we had two churches -- except during the summer."

Lowrie presented Ford's with a facsimile machine and Hewitt with a Waterford crystal version of the Capitol dome.

After the speeches, guests were bused over to the Willard Hotel -- except for people like Occidental Petroleum's Washington chief William F. McSweeny and his wife Dorothy and the AT&T contingent, all of whom traveled in limousines as long as the buses. Nice note -- Ford's had valet parkers who removed patrons' cars at the theater and delivered them afterward to the Willard.

Chief attractions at the Willard, other than the lavish loaves and fishes, were the players. "I learned how to play the evangelist Gantry by watching Jimmy Swaggart," said Casey Biggs, who comes from Ohio. "I learned from Pat Robertson and Swaggart -- you have to be frightening, and charming and sexy -- you have to have the power to hold the audience in your hand. I was raised a Catholic, and we don't do all those things. I don't know what my mother will say."

Sharon Scruggs, who plays the evangelist Sharon Falconer, at least comes from Memphis, where evangelists are at home. She said she'd checked to see if Lincoln was in his box tonight -- a recurring legend among actors who play Ford's -- but hadn't seen him. Everybody else was there.