He wanted to build a bomb from acetone peroxide and detonate it in the subway. His only success in this grand plan would have been blowing himself up in his apartment as he closes the lid on his explosives, the friction between the lid and TCAP residue instantly detonating the mixture.
(As always, their stupidity is our best protection, not the NSA)
Are they all dumb and stupid? If so then everyone who's been claiming that terrorists are already encrypting all their communications and using proper COMSEC are incorrect.
If they're not all dumb and stupid then simply sitting on our hands waiting for the next massive attack is folly, and more importantly it's something the American public won't long stand for.
The nation has a long history of action where their sensibilities are offended, even where it doesn't maximize the cost/benefit analysis. Guess when this was said: "Millions for defense, but not one cent for tribute!".
A President or Congressman who tells the public that their counterterrorism plan consists of simply relying on the fact that it's not like lots of people will die will be the first ones out of office. Even Rand Paul agrees with counterterroism for crying out loud, he argues that you should have specific targets and then collect instead of collect first and wait for targets as the NSA is doing now.
It's not that they are all stupid, but a rational cost-benefit analysis would dictate that significantly less money be spent on so-called national defense and military programs than is spent today.
The reason we spend money on "anti-terror" stuff is b/c terrorism is actually a highly efficient/extreme form of propaganda messaging, and propaganda is something that states care very much about. It cuts to the core of the legitimacy and efficacy of the state as an institution and so what is being protected is institutional credibility, not human life.
(As always, their stupidity is our best protection, not the NSA)