Think “Alice’s Restaurant” is a period piece? Well, OK, but “27 8-by-10 color glossy photographs with circles and arrows and a paragraph on the back of each one” has entered the lexicon as a synonym for mindless American bureaucratization. And you can hardly argue in this day and age that protest songs have lost their relevance. Nor, surely, would you want to say that down-home storytelling no longer entertains. In fact, Arlo Guthrie’s mastery of language, song, and Zeitgeist—not to mention the folk tradition so well exploited by his genius father—makes a case for him as a national classic, a treasure on a par with Copland or Bernstein. And by coincidence, Guthrie will be performing his stuff alongside theirs, when he joins conductor John Nardolillo and the Metropolitan Symphony Orchestra tonight at 8 p.m. at the Kennedy Center’s Concert Hall. $25-$45. (202) 467-4600. (Caroline Schweiter)