It's a sad celebrity ritual. Tragedy strikes somewhere in the U.S., and a star uses Twitter to politicize it for their pet cause. Henry Winkler of Happy Days fame joined the club earlier today. The actor rushed to Twitter today after news broke that a shooting at the U.S. Navy Yard in Washington, D.C. left several people dead. Many details are still unknown, but that didn't prevent Winkler from assuming gun control would have prevented the shooting.