In his memoir Days and Nights at the Second City, Second City cofounder Bernie Sahlins cites the troupe's roots in ancient Greek street theater, namely "cheerfully obscene sketches that lampooned not only the gods but politicians, philosophers, generals, and other public figures." For its annual appearance at the Theater on the Lake, Second City will put special emphasis on the politicians, generals, and "philosophers"--government propagandists and media spin doctors--who've shaped our country's military record since 1959. That was the year Second City was founded, partly in reaction to the complacency of the Eisenhower era, and director Anne Libera and her ensemble have rummaged through 45 years' worth of material to chart the path that led to our overseas adventures today. Given the current taste for political commentary, whetted by Fahrenheit 9/11 and cable-TV talk shows, vintage vignettes about Vietnam, Grenada, and the gulf war as well as skits from Second City E.T.C.'s cutting-edge revues of the past couple of years should be received as entertaining as well as educational. Theater on the Lake, Fullerton and Lake Shore Dr., 312-742-7994. Opens Wednesday, July 14, 7:30 PM. Through July 18: Thursday-Saturday, 7:30 PM; Sunday, 6:30 PM. $15.