It's almost as if wartime collaborators seeking to follow up on an attack that killed 3000 civilians are treated more harshly than freelance terrorists.
As I recall, the evidence against Rudolph was a lot less clear-cut and the investigation had been bungled previously, giving him a good number of openings at trial to poke holes in the government's case. Given that, it made a lot more sense to offer him a plea and ensure that he went away forever. No one was finding Tsarnaev innocent.
Nobody's saying Tsarnaev was innocent.
No, what I'm saying is that the reason he didn't get offered a plea deal compared to Rudolph is because the government was far more confident in their ability to get a conviction.