Ten thousand people in the mood for a little honky-tonkin' pulled off the road into the Capitol Centre last night to hear good ole Willie Nelson. And even though the stage was cluttered with Nelson family, a delegation from the Russian embassy and a contingent from the White House, it's obvious that Nelson's largest constituency is derived from roadhouses, real and imagined.

Nelson's notoriety as a cult figure in country music has often obscured his two major contributions to the genre: a substantial, consistent body of original material and a decommercializing, anti-Nashville stance that revitalized the music with a cutting and introspective edge. And even though Nelson's music is filled with good-hearted women and good-timing men, they act within real, not ritualized, life dramas.

The result has been a cross-cultural fertilization equally atttactive to outlaws and in-laws. Nelson's nasal tenor is unaffected, yet thoroughly affecting, and his terrific band-with Leon Russell on piano for this phase - knows when to punch out the melodies and when to sit them out.

Anyone who can make Russian diplomats dance on the edge of the Capitol Centre stage-the Chinese ambassador was reported elsewhere in the hall - has found something of a universal pulse. For Willie Nelson, country music is merely a category, not a boundary. That may be one reason he was invited to the Soviet Union last night by his newest fans.

Toward the show's end, Willie's daughters, Paula Carleen and Amy, joined him on a pair of rousing gospel tunes, a little bit of "Amazing Grace" in the midst of a lot of Amazing Willie, a truly unique American artist.