John Phillips walked out of Union Station yesterday remembering an earlier good time in Washington: skipping high school in Alexandria to cheer the Senators baseball team on their return from a nine-game winning streak...and getting suspended when his picture appeared in the next day's paper. "I didn't like class," he chortles.

For a time in the '60s, though, Phillips was class, writing the songs and arranging the voices and shephearding the career of the Mamas and the Papas as they reacted to the British invasion with 100 percent American pop classics like "Monday, Monday," "California Dreamin'" and "Go Where You Wanna Go." Their first album was titled "If You Can Believe Your Eyes and Ears." Phillips, 46, was bringing the new Mamas and the old Papas to Washington for a concert last night at the Wax Museum.

Close your eyes and you can probably call up the original group's colorful image--tall, gaunt, Papa John and his beautiful, unsmiling wife, Michelle; the stolid, angel-voiced Denny Doherty and Mama Cass Elliott, the splendid hugeness whose lungs were an elegant foghorn.

People remember the group's contrapuntal harmonies as if they were interwoven yesterday, but the 12 years since the Mamas and the Papas divorced each other on the Ed Sullivan show have dulled some of those memories.

Such as the fact that less than three dozen concerts were given during the original group's turbulent three years. "We'd get to a city, and then we'd have a fight, and then we'd have to give everybody back their money," Phillips recalled. So he took the money he'd wisely set aside, and he hid in the canyons of Malibu. Michelle divorced him and wound up in the movies. Doherty went back to Canada and ended up on television. Cass Elliott pursued a solo career and choked to death on a chicken sandwich in London in 1974.

Papa John went to London and fell into faster company than the laid-back L.A. drug scene. "It took me six weeks to get addicted and six years to get over it. I thought I was above that. I woke up one morning shaky and with a runny nose, said to my friend 'I must have the flu.' He said, 'No you need a fix.'"

In 1980 Papa John got busted for possession of cocaine; his daughter Mackenzie, then 20 and a popular star on the television comedy "One Day at a Time," was dropped because of drug use. Phillips' son Jeffrey, who is now 24, and his wife, acctress Genevieve Waite, were hooked as well. "I realized they were all imitating me," says Papa John. Facing 45 years in prison, he entered the entire family into a drug rehabilitation program in New Jersey: 18 months of probation--and autographs for fans who remembered better days.

So maybe it's time for the Mamas and the Papas again, Papa John thought. "Everyone said, 'Get a black girl or someone very skinny or someone from France or a chinese person...not someone who looks like Cass.'" He called up Spanky McFarlane, whose Our Gang had just broken up. Spanky and Cass were friends, sounded a lot alike (they were about to cut a record together before Cass died) and she's...sizeable enough to step into Mama's mumus. Michelle had become an actress, so Phillips evened the score by turning Mackenzie into a singer. "She grew up with a lot of this material," he points out. "They were her lullabies." Doherty came back from Canada. "Everyone's a tone lower," says Phillips, "but it's the same falling harmonies."

People like the sound, they cheer the old songs, they like the new Mamas just fine. "Mackenzie adds a new dimension because a lot of young people come to see her," says Phillips. "It's like the circus, we have 'em from six to 60 in our audience."

Daughter-Mama Mackenzie has been off drugs for a year, is back on "One Day" from time to time. There is a sense of being saved, not just from drugs, but from the edge of memory. It may not be the second Golden Era, but it beats the abyss. Papa John, who produced the world's first rock festival at Monterey, remembers the other stars on the bill: Otis Redding, killed in a plance crash; Jimi Hendrix and Janis Joplin, dead of drug overdoses. "It's all so strange," he says quietly. "I don't know why I'm alive...but it feels wonderful. It all sounds so good and we're so happy doing it. There's no way we're not going to make it." Again.