Ineptitude is no defense against conspiracy (which is the much easier crime to demonstrate, btw; at this point it's virtually a slam dunk).  

If it were, there'd be a lot of wannabe-terrorists who'd be walking the street today instead of behind bars:

http://listverse.com/2016/02/04/10-embarrassingly-dumb-terror-plots-that-failed-miserably/

No, incompetence isn't a crime -- but it's certainly not a get-out-of-jail-free card.