By Matthew J. Lacombe, Los Angeles Times (TNS) Six of the 10 deadliest mass shootings in U.S. history occurred in this decade. Although these massacres are always followed by intense public debate about gun control, they rarely lead to meaningful action in Congress. Should we expect anything different after the rampages in Gilroy, El Paso and Dayton, which killed 34 people? Pessimists would say no.