In the world of Waylon Jennings, the law is something to be outside of, barrooms are smoky, bottles empty; women are difficult, or at least challenging, friendships enduring. It's a complicated black and while world that has evolved in reaction to country music's glossy and simplistic colorization.

Jennings drew a near-capacity crowd to Constitution Hall last night in a fund-raiser for President Carter's reelection campaign. Along with Willie Nelson and Kris Kristofferson, he is one of the Nashville mavericks who shook country music from its traditionally staid roots by taking it off the assembly line and personalizing it. Jennings also invested country with a heavy rock accent, encouraging the country-rock fusion from both ends. (He was, of course, an original member of Buddy Holly's Crickets).

Samule Beckett would have titled last night's program "Waiting for Waylon." When Jennings finally showed up after 90 uninspired minutes of Jessi Colter (Mrs. Jennings), the original Crickets and odd songs from his band, it took him almost all of his hour-long set to overcome the inertia. When he sang "Are you Redy for the Country" the answer was obvious. As a country singer, Jennings has few equals, particularly since he is so deeply rooted in the gritty toughness of classic rock vocals. Singing a commendable number of his classic rock vocals, he straddled the nuances of ballads and broadsides with equal ease.

Waylon Jennings is a genial outlaw who has obviously discounted the myth that his music has evoked for his public. It would have been delightful if he had made an earlier and longer night of it.