evidence: Three months after they killed Al Qaeda leader Osama bin Laden in neighboring Pakistan and cemented their place in military legend, the SEALs suffered a devastating loss when nearly two dozen of the elite troops were among 30 Americans who died when their helicopter was shot down in Afghanistan early Saturday. [...] The downing of the U.S. helicopter in mountainous Wardak province comes at a crucial juncture of the war, as the U.S. begins a drawdown in troops in a prelude to a full-fledged withdrawal. [...] But they have been deadly for U.S. troops. Before Saturday, the highest single-day loss for the U.S. military in Afghanistan came on June 28, 2005, when a Chinook carrying 16 Navy SEALs and Army special operations troops was shot down in Kunar province as it tried to rescue four SEALs in a firefight. All 16 were killed in the crash, and three SEALs died on the ground.