After 11 hours of deliberations over two days, a federal jury on Wednesday found Dzhokhar Tsarnaev, a failing college student and the youngest child in a dispersed Russian immigrant family, guilty of the 2013 bombings at the Boston Marathon, the worst act of terrorism on American soil since the attacks of Sept. 11, 2001. The bombings almost two years ago transformed one of the world’s most prestigious road races on a glorious spring afternoon into a scene of carnage with bodies strewn across Boylston Street, giving the nation a horrifying glimpse into the consequences of homegrown, self-taught terrorism. The bombs,...