Any hope the defense has of saving Tsarnaev's life is in convincing the jury that he was just a deadbeat, pot-smoking college student, under the sway of his older brother Tamerlan, the real jihadi. A demonstration of what they're up against - say Boeri and Cullen - came in Day 8 of the trial, with the first testimony from one of Tsarnaev's old friends, Stephen Silva.