When Lyndon Johnson summoned Jack Valenti to fly to Washington aboard Air Force One on that traumatic 1963 day in Dallas, the dapper Houston advertising man figured he’d be a short-timer.

“I thought I was going to be here two or three years and go back to Texas,” Valenti recalled recently.

“But of course, those that come to Washington thinking that always have to renege on those earlier pledges,” he continued. After nearly three years in the Johnson White House, he has spent 38 years as the movie industry’s top Washington lobbyist. “It’s a bewitching town,” he said.

It’s also one, he noted, whose politics have changed substantially – and not for the better – since the mournful weekend on which he arrived with Johnson after John F. Kennedy’s assassination.

“The biggest change I’ve seen is the rise of virulent partisanship, which creates a hostile environment and is not soothing or beneficial to either party,” he said. “And I have no idea of how to deal with it.”

He recalled the days when Johnson was the Democratic president and Sen. Everett McKinley Dirksen of Illinois was the Senate Republican leader.

“Dirksen would arise on the Senate floor and eviscerate Johnson,” he said. “And then, four hours later, they’d be in the White House, joking about it.

“Johnson would say, Everett, I wouldn’t treat a cut dog the way you treated me.’ And Dirksen would say, Well, Mr. President, you know, I have to tell the truth.’ And they would joke with each other and tell stories.

“And when they got through, Johnson would get some votes for his civil rights bill; the Republicans and Dirksen would get some appointments to various regulatory agencies. Or they would come to grips on whatever bill was in the Senate where they could compromise on. And the government worked.”

The reaction to the announcement he will retire Sept. 1 as president of the Motion Picture Association of America illustrated the partisan climate. A top conservative Republican, Grover Norquist, denounced the fact he will be succeeded by another Democrat, former Kansas Rep. Dan Glickman.

Though Washington has gone from Democratic domination to GOP control, Valenti cautioned that power swings back and forth like a pendulum.

“No one stays in power forever,” he said. “All things are in a state of flux. Power passes; power changes. That’s the cyclical environment that is absolutely without doubt.”

Will John Kerry seek a more bipartisan approach if he wins? “I have no idea about that,” said Valenti, who cultivated a reputation of working with both parties.

“All I know is I think most people would like to live in a neighborly environment rather than a hostile environment. That doesn’t mean you love all your neighbors, but you get along with them because you’re on the same street.”

Of the seven post-LBJ presidents, Valenti has a surprising favorite: George H.W. Bush, father of the current chief executive.

“He was a decent, good man with great fidelity to his country, a commitment to decency,” he said.

As for Johnson – he once said, “I sleep each night a little better, a little more confidently, because Lyndon Johnson is my president” – Valenti said he believes his former boss’ reputation is continuing to rise.

“A big reason for it” is that Johnson’s tapes of his telephone conversations with aides and colleagues, released in recent years, enabled people to see “how his innermost thoughts were being expressed, how he dealt with congressmen and senators, showing he was one of the most extraordinary leaders of modern times.”

He cited Johnson’s success in fostering civil justice, human rights and civil rights by winning approval of the Civil Rights Act of 1964, the Voting Rights Act of 1965, Medicare, the war on poverty, federal aid to education and the Fair Housing Act of 1968.

“All these things were to the benefit of people who were barren of hope and living on the margins of life,” he said. “So in that sense, more and more of what he did is beginning to overcome the stigma and the fungus of Vietnam that lay upon the face of his presidency.”

Carl Leubsdorf is Washington bureau chief of the Dallas Morning News.