The jurors knew that the failure to convict would make them pariahs among their brainwashed families, friends, and communities. In former times when the US had the rule of law, the irresponsible statements by public officials repeated endlessly in the media would have likely resulted in the court dismissing the case on the grounds that public authorities had made a fair trial impossible.

Tsarnaev's attorney knew that evidence would play no role in the case and focused on trying to save Dzhokhar from a death sentence by blaming the older brother who was killed by police. Perhaps Dzhokhar's attorney remembered what happened to attorney Lynne Stewart who was sentenced to prison for representing a client for whom the government only wanted a pro forma representation.

West Point graduate and former US Army officer Joachim Hagopian describes the orchestration and avoidance of evidence that delivered the mandatory conviction: 

http://www.globalresearch.ca/boston-marathon-bombings-guilty-verdict-exposed-as-a-gross-travesty-of-justice/5442240

A fair trial is among the many victims murdered by Washington in the 21st century.