In fact, the U.S. had so much knowledge of these people and their activities, I am suspect they just allowed those at the marathon to be blown away...What the government's motive for this was, is anyone's guess.
“In fact, the U.S. had so much knowledge of these people and their activities, I am suspect they just allowed those at the marathon to be blown away...”
See, this is where you’ve lost me. The government knew at least one of these guys was a radical, that he went on some jihadist websites, and went to Russia possibly to try to hook up with terrorists. We’ve got no information that they knew of any active plot that was going on, so you’re jumping to a conclusion (that they might have allowed the bombing to happen), when there is no evidence the government knew there was going to be a bombing.
What was the government supposed to do? Arrest the guy for having politically incorrect views? Or for voicing radical opinions? Their hands are tied by the 1st Amendment there.
Could they arrest him for meeting up with foreign terrorists? Yes, but there is no evidence that he ever actually managed to meet up with any, so they couldn’t do that.
Could they deport him just because they had evidence he was a rotten egg? Maybe, but he had gotten his citizenship already, so I think that is out the window too.
So, what would you have had the government do to stop this, that was actually within their legal limits to do?