No, with that premise it would be logical to expect them to do the same thing they've always done - try to cover up their own incompetence (badly) and, as long as bad things happen, use those bad things to further their own political goals. That looks familiar - it's what the Bush administration has done.
It is a HUGE leap of logic to assume that they would make the step to blowing up their own citizens, expecting it not to be revealed.
It didn't in Hitler's case. He had his own parliamentary building, the
Reichstag building, set ablaze and blamed it on the communist in order to pass
Article 48 which allowed him bypass the parliament in his decision making. Of course he promised to only use it in times of war. Sound familiar? The alleged arson was sentanced to death, but afterward in the Leipzig Trial it was found that the Nazi party itself orchistrated the events.
So by no means is such an event impossible to be commited. And how about that good ole patriot act?
Did you know that our government is now capable of holding
military tribunals? Check this out, for interests of "national security" they don't have to reveal evidence, don't have to publicize the trial, don't have to disclose thier voting, and look at this liitle excerpt here: "Any individual subject to this order shall, when tried, be tried by military commission for any and all offenses triable by military commission that such individual is alleged to have committed, and may be punished in accordance with the penalties provided under applicable law, including life imprisonment or death." Read it all for yourself. All you have to do is be accused of being a terrorist, or even of supporting terrorists in any way. (and who knows who they're gunna want to call terrorists)
So in light of these facts, I don't think it's very inconcievable to imagine that our government would try to orchistrate something like 9/11. I personally don't think they're as stupid as they'd like us to believe.