Even if these are the guys and are truly guilty, the government still has some explaining to do.
How so?
There is that runner from the University of Mobile that was interviewed and talked about the extra security, bomb sniffing dogs and announcements about a drill.
There are the 2 guys that appear to be Craft International personnel with the earpieces.
There are tweets from the Boston Globe about planned explosions as part of the drill.
My theory (subject to revision):
It appears the Gov't had advance knowledge of some threat, even though they deny it. The drill was just a cover-up to mask the real threat. They don't want to answer for the carnage they allowed by not cancelling the Marathon. They willingly put people at risk. Being the opportunists they are, they will now use this to strip away even more liberties.
We are not getting the whole story. The story has already been shaped and whatever happens will be made to fit the official story line.