The best historic drama lets us walk away with a strong idea that transcends mere images and information from our past. History Theatre's "1968: The Year that Rocked the World," largely an essay in glib nostalgia and ardent broccoli theater, redeems itself with just such a concept -- proposing that humanity's ability to persevere is eternal regardless of the agonizing dislocation within any single year.

The show, directed by Ron Peluso, uses a "Laugh-In" rat-a-tat-tat style and a trivia timeline to stitch together short vignettes.

Among the more affecting plays is Kevin Kautzman's "Rosemary," in which actor Karen Weber portrays singer Rosemary Clooney in the wake of Robert Kennedy's assassination. Rosemary is a metaphor of a bereft nation whose optimism has been pierced by three bullets. Excerpts from speeches, spoken by Randy Schmeling, recall Kennedy's amazing gift for compassion.

Kim Hines' meditation on Olympic sprinters John Carlos and Tommie Smith uses a media gimmick that had us stabbing at our wrists, but the piece mellows into substance as a man (actor Joe Nathan Thomas) reflects on how Carlos and Smith's gloved-fist salute at the Mexico games was a proclamation of presence for African-American men. "They showed black men being men," Thomas says powerfully.

Playwright Dominic Orlando casts his withering cynicism on the plump target of Richard Nixon. E.J. Subkoviak does a fine turn as Nixon's chum John Mitchell, and Paul de Cordova channels Dan Ackroyd to send up the Republican nominee.

Rhiana Yazzie's play, "The Corral," finds in the experience of two American Indians (M. Cochise Anderson, Rob Thomas) the humiliations that fueled the American Indian Movement. Christina Ham uses a similar form to explore the intense financial pressures felt by sanitation workers on strike. A third two-hander, "Welcome Home" by Reginald Edmund, visits the trauma faced by a returning Vietnam vet. These are worthwhile, though perhaps too earnest.

It is Mat Smart's "Apollo 8," inspired by images of Earth sent home by orbiting astronauts, that conveys something greater than the sum.

Smart wrote about Garret Reisman, a real astronaut born in 1968. Reisman (Schmeling) travels back to that Christmas Eve and asks his mother (Lindsay Marcy) how she and her husband (Eric Knutson) could have imagined bringing a baby into the mess of 1968. She answers with eloquent simplicity: "No matter what is happening in the world, you take care of your children." We then hear the astronauts' famous recitation of the Genesis creation story -- a timeless affirmation of the world's constancy -- and the effect is devastating.

Peluso lets this show go on far too long. But in the final breaths, as was the case in 1968, a message of hope carries a measure of redemption.