Folks tuning in tonight to "Kraft Salutes the 25th Anniversary of the Country Music Association" (Channel 9 at 9) may not recognize Constitution Hall, whose stage was redesigned in Las Vegas Modern style for the taping of the country extravaganza last month.

But if the hall isn't familiar, the audience certainly is. On one side, President and Nancy Reagan, on the other, Vice President and Barbara Bush, and on the floor, such senators as Edward Kennedy (D-Mass.), Howard Baker (R-Tenn.) and Robert Byrd (D-W.Va.). The latter two eventually wend their way to the stage, Baker to deliver a paean to the roots and spirit of country music, and Byrd to saw at his fiddle in the show's brief tribute to bluegrass.

Kenny Rogers kicks things off with some kind words for Washington impresario Connie B. Gay, who presented the first nationally televised country music show back in 1948 and went on to become a founding member and first president of the CMA.

There is a genuine low-key warmth and camaraderie among the performers. Some highlights: Eddy Arnold, Tennessee Ernie Ford and former Washingtonian Jimmy Dean, singing about the good old days and coming across as old smoothies and country gentlemen; Loretta Lynn's tribute to Patsy Cline; and the standing-ovation show stopper, a duet by the two blind country superstars, Ray Charles and Ronnie Milsap.

Poor Charlie Daniels has a devil of a time getting his fiddle in tune, but otherwise there are surprisingly few sour notes during the program's 90 minutes. An endless medley of number one country hits is sung somewhat raggedly by Anne Murray, Barbara Mandrell, Glen Campbell and Larry Gatlin. A more serious faux pas involves Alabama's performance. The group, apparently miffed at the horrid sound during its February Grammy-awards performance, taped its song beforehand without the audience. Still, there's a shot of Vice President Bush smiling and clapping along.

There's also the ongoing problem of Hollywood's hokey orchestral bridges, this time sounding like outtakes from the soundtrack of the TV series "Seven Brides for Seven Brothers." Television seldom trusts the music it honors, whether it be country, rock or jazz, so audiences get diluted, homogenized impressions rather than the real thing. Maybe that explains classical violinist Eugene Fodor's appearance, which shows just how far uptown country has come, something also evident from the tuxedos sandwiched between some performers' cowboy hats and cowboy boots.

And then there's Willie Nelson in his sleeveless T-shirt. The producers don't allow him the extra songs he snuck into his portion of the gala, which they could have done by excising an unnecessary airport scene. The all-too-brief tributes to Jimmy Rogers, Tex Ritter, Patsy Cline and Hank Williams feature some vintage film clips. It would have been nice to get more of a sense of history and less a parade of achievement, but the producers have played it fairly straight from the heart.

At the end, when Ray Charles slides into "America the Beautiful" and is joined by the entire cast, what could have been hokey seems simply grand--country music on a clear Washington night when the stars are out in force.