Baby, baby. Where did our love go?

Where did our youth go?

It's the same old song, but how glorious to hear it again. The poor old '60s have taken a terrible trashing, but if there was one thing about them we would wish back just as it was, it would be Motown. If you were a white kid, loving Motown was almost a political act, and you felt so good about it. If you were a black kid, it had to be heaven. You could say to your white friends, "This is ours. See what you've been missing?"

Tonight's NBC special, "Motown 25: Yesterday, Today, Forever," a two-hour compression of a celebratory reunion held in March by artists currently or formerly associated with Detroit's pop-music renaissance (maybe just 'naissance), is more than an entertainment. It is an astonishment. For millions of those who watch, it will also be a personal matter. This was music that meant as much to a generation as any music ever did.

The old protest tunes and folk songs of the '60s sound so corny now--and, ugh, to think how self-righteously moony we once got about them! But on tonight's special, at 9 on Channel 4, the Motunes sound better than ever. They are perfection. There's such a purity to them rediscovered in, more or less, their natural state, especially now that it's the retread '80s and a number of white artists insist on rerecording many old Motown hits, never duplicating the originals.

There are so many performers on the show, and so many of their classics are cut short, that it's a pity somebody thought it necessary to include an appearance by Linda Ronstadt, who is a fine performer but not terribly relevant here, and another by Adam Ant, flashing his famous navel. The sole highlight of Mr. Ant's performance is that during it, Diana Ross wanders out absent-mindedly from the wings and wiggles through something that might pass for a dance. She has so much hair now, Newton would marvel that she can remain erect.

Although "Motown 25" had to be edited down from three hours to around 115 minutes, the overwhelming warmth and luster of it seem to have been brilliantly preserved by producer-director Don Mischer and executive producer Suzanne de Passe, Motown's president. One could certainly quibble over priorities, and there really isn't enough of anyone (save Adam Ant and Linda Ronstadt), but when Stevie Wonder shucks the highfalutin stuff of recent years and dips back in time for "My Cherie Amour," and asks the audience to join him on the "La La Lahhh La La La's," the sense of sentimental event is sensationally moving.

For about the first 90 minutes, it's a show consisting almost entirely of stoppers, starting early when Smokey Robinson is re-united with The Miracles for "Tears of a Clown." Wonder also sings "You Are the Sunshine of My Life." The Four Tops and the Temptations are re-united for a group medley, the Tops in silver silk tuxedo jackets, the Temps in black, all wearing red pocket handkerchiefs, everybody moving in the stylish clockwork unison they exhibited a couple of decades ago.

During a mock deejay session cohosted by Howard Hesseman and Tim Reid, formerly of "WKRP in Cincinnati," the memory-joggers include Martha Reeves (without, alas, the Vandellas) and a too-brief "Heat Wave," and Mary Wells, who appears to be dressed in a large cloud, and a too-brief "My Guy."

But then, in the second hour, the special goes from the sublime to the sublimer--sublime to the nth degree; the original Jackson Five are re-united. Mischer cuts briefly to a shot of a little boy in the audience who, though obviously too young to remember them, is bouncing up and down in elation. They sing "I Want You Back" and "I'll Be There." They hug. And then Michael is left alone on the stage to sing his current (non-Motown) hit, "Billie Jean," and proceeds to set a new standard in sheer, shocking electrification.

Jackson's voice hasn't really changed much over the years. But the moves have. Oh, how they have changed! Michael Jackson is more dazzling than a Fourth of July fireworks display. He redefines showmanship right in front of your amazed little eyes.

The reunion of Diana Ross and The Supremes was to have been the climactic moment of the evening, but the Jacksons really aren't topped; Ross sounds out of voice, even out of sorts, and according to published reports, botched up the show's finale. But Berry Gordy Jr., the entrepreneur of inestimable faith and resourcefulness who founded Motown and, says host Richard Pryor, recruited most of its phenomenal talent from among "kids off the street," bounds down to the stage to join in a closing sing-along.

In addition to the performances, the program includes film clips from Motown history, including the Jackson Five's crudely shot 1968 audition tape; a clip of Ed Sullivan introducing "Dye-anna Ross and The Supremes," then stalling when told Ross is making a wardrobe change and joking, "Dye-anna Ross will be fired for this"; and a medley of Grammy Awards presenters announcing the winning name of "Stevie Wonder" over the years, one presenter a still-robust (now seriously ill) Kate Smith.

Dick Clark offers a history of Motown in which he recalls that many early Motown LP covers made a point of not picturing the recording artist because a black face was considered an impediment to sales. Have we come a long way? Not particularly. MTV, the Warner-Amex rock video channel, has been severely criticized for refusing to play more videos by black artists. Motown represented a triumph of what's called in the movie business "crossover": black-oriented entertainment with a strong appeal to white audiences. But there doesn't seem to be as much crossing over as there used to be, except for the occasional Richard Pryor and Eddie Murphy movies, or such saccharine-coated cookies as the lamentably self-congratulatory McCartney-Wonder "Ebony and Ivory."

But once upon a time, there really was a Motown, and "I Hear a Symphony," and "Dancin' in the Street." And it really did bring a lot of us, at least momentarily, together.

For two hours tonight, sweet dreams are recreated, youth recaptured, an era invoked, and in such splendid fashion that it becomes, at one or two points, almost too transporting, maybe even a little too wonderful. So much so that some may feel inclined to shout out, tearfully or otherwise, "Stop--in the name of love. Before you break my heart."