Yes, but conservatives are reaching putting forth theories that Democrats staged this to help at the polls. Again, the obvious answer is usually the correct answer.
Wouldn't this, by your own logic, be an incredibly stupid* time for right wingers to engage in this behavior? Let's say all bombing attempts were successful...this would help the R's how? I'm not of a conspiratorial bent but the timing and intent would seem to be counterproductive for the right wing. Wouldn't you agree?
*I don't want to rule out stupid/crazy superseding any of the above. There are some massively messed up minds out there.