If these events happened today.....
Let's say the 'terrorists' were smart enough to evade local authorities and the federal officers (FBI, CIA, NSA). Now let's say that bombs are going off everywhere killing thousands of people (every day life in the Middle East).
You would see Obama send in the army. No doubt that they will try to kill an a few ants with shotguns and smart bombs. This time, there will be no "Hub" to preach the Constitution. There would be no 'good guys' to stop the 'bad guys'. Right now, all the players are playing for the same coach. They are all on the same team. So if they bend the law, then so be it. 9/11 made sure they can do so without losing their jobs or going to jail.
There would be concentration camps. There would be massive racial profiling. There would be random, warrant less shakedowns and arrests. There would be torture and murders. There would be suspension of Habeus Corpus. There would be suspension of posse comitatus.
But the worst part is that the American public, who most are plain sheep, would be all for it. You'll hear chants of "Kill them rag heads", "Get rid of them Jihads", "Nuke the Middle East", "Good riddance", "When can I watch football again?". There would be very little support of sympathy for the Arabs.
Basically, it would be twice as bad as what we saw in the movie.