Norman Lear has come up with another first: America's first left-wing patriotic rally. Is it high time for that? Maybe not, but the show itself, "I Love Liberty," is a predominantly high time--an agreeably corny, sincere and fitfully thoughtful rouser taped last month in Los Angeles and airing on ABC (Channel 7) tomorrow night at 9.

Lear came to Washington to host a Hill screening of his show a week ago, and, as always, he was bubbling over with enthusiasm. "The show is everything I hoped it would be," he said. "I don't remember feeling better about anything." Lear himself may be a liberal, but he's designed the program to be "open-minded" and to appear as bipartisan, or multi-partisan as possible, partly to keep the network out of hot water for airing it. As television, it's unimpeachably wholesome. One could watch it and have innumerable misgivings about it and yet not doubt that Norman Lear's heart is in the right place. Not that heart.

Among other things, "Liberty" features: 9,000 cheering spectators; the Muppets as members of the Continental Congress; Barbra Streisand--taped separately in England--singing "America the Beautiful" with the U.S. Air Force Band in Europe (and singing pretty again, like she did before she fell in with the Hollywood rock-sleaze set); and a production number performed by 1,600 people, including baton twirlers, unicyclists and five marching bands, introduced by Sen. Barry M. Goldwater (R-Ariz.).

Wow. Norman Lear is trying to steal back some of the patriotism that he feels has been co-opted by the so-called New Right. He says liberals and moderates can get just as emotional about their country as super-conservatives and endeavors to prove it with this enormous and dazzlingly well-staged whiz-bang. Among its heroes is the great Robin Williams, who cuts through the cant and delivers, beautifully, a monologue as the U.S. flag. He actually impersonates not only the flag but several states of the union. It's the most captivating part of the show, followed closely by Geri Jewell, an actress who has cerebral palsy and who tells a few jokes and then says, "It's a lot harder to fight for the freedom of speech when you can't talk and the freedom of assembly when you can't walk."

A Yankee-Doodley production number led by Gregory Hines is very persuasively ebullient; Peter Matz, who made old songs sound new again with his musical arrangements, did much to keep this thing buoyant. It's when people start talking that unpleasant memories of preachy high school Flag Day assemblies start creeping into one's mind.

The program, meant as a celebration of American diversity of opinion and the First Amendment that protects it, was produced by Lear's People for the American Way, a group formed to counter the influence of the Moral Majority and other such outfits, but Lear insists "I Love Liberty" is a purely positive hoo-rah, that "the show isn't pointing a finger at anybody." At one point in it, actor Martin Sheen says how wonderful freedom in the U.S.A. is and exhorts the audience, "Come on, let's hear it for us!" Why does Norman Lear think we should come on and hear it for us at this particular time?

"In the last three or four years, I've read the results of studies and polls and research that say Americans are alienated, that they have lost hope in the future, that they feel they don't matter. And I thought, what a terrific time to help people understand that the turmoil they're in has always gone, in varying degrees, with the territory. It's something to celebrate, almost.

"I also thought it was time to take back the flag, for all of those conservatives and centrists and progressives who have always adored the symbols of this nation but been reluctant to praise them, for fear they'd be put in the same bag with the far right."

Lear is asked if he wouldn't resent such a TV special if it were produced by right-wingers, and he says such a show would be a lot different from his. "It would not have a sense of humor, for one thing. It would take itself 100 percent seriously. And it wouldn't have a group of five minorities talking about their grievances with society." And, he notes, it wouldn't have stars like his--not Jane Fonda, nor maybe even Kristy McNichol and Kenny Rogers and Burt Lancaster and Walter Matthau. It might have Pat Boone and Anita Bryant and Efrem Zimbalist Jr., however; that would be enough to sink it right there.

The Rev. Jerry Falwell, head of the Moral Majority--and an enemy of Lear's group--wired Lear asking that he be allowed to speak on the program. Lear says he rejected the notion not because he didn't want Falwell but because he didn't want speeches. They have "a big yawn factor," he says. He certainly doesn't pretend to be a fan of Falwell's; what Lear says he objects to about the New Right is its use of fear tactics to lure the justifiably worried, the "decent, fair-minded Americans" who feel "alienation and helplessness."

"It's all fear, fear, fear, fear, everywhere you turn, from TV evangelists Pat Robertson to Jim Robison to Falwell, all of them, fear," Lear says. "Now by some counts they've only attracted 4 or 5 million people, so we asked ourselves, where are all the rest of the people who have the same needs, and how will we go after them? And we decided, our thrust must not be negative, that we should offer hope, not fear, and the belief that we matter. I hear so much about America's loss of faith in tomorrow, but that can become a self-fulfilling prophecy. There is no future if you have no faith in it. I mean, what are we gonna do without hope?"

There will of course be viewers who will see Lear's credit at the beginning of the show and reject it outright because of his political posture. He is asked why he would risk aggravating such people further by coming out in support of Gore Vidal, who recently announced his futile candidacy for a U.S. Senate seat from California. Lear conceded Vidal stands no chance of winning but said, "It'll be terrific to have that intellect in the campaign. Not since Adlai Stevenson have we had a person with that much wit and intellect running for national office. It will elevate the rhetoric."

Lear says also, when asked, that he has not sent Ed Asner any money to be forwarded on to guerrillas fighting against the U.S.-backed regime in El Salvador. But he defends Asner's right--and his own right-- to take stands on public issues. "Why should people in our business have to forfeit their right to speak out? I have always expressed my rights as a citizen. Nobody says anything when Joe Coors, the head of a brewery, speaks out, or when J. Willard Marriott, the head of a big hotel chain, speaks out. Just because I made my achievements in show business, must I forfeit my rights, my values, as a citizen?"

In the show, Sheen talks about a mythical grandmother who regularly fired off letters to the president. This is actually based on Lear's grandfather, who would address FDR as "My dear darling President" even when dashing off a gripe. Lear lived with his grandparents for a time in a third-floor walk-up in New Haven, Conn., he says, and it was his job to go downstairs and get the mail. He remembers with a smile the kick he got when there was an envelope in the box with "The White House" as the return address.

Norman Lear will be 60 on July 27, and he's a little worried about that. He shouldn't be. He's still one of the youngest men in all of television.