Fear is a great motivator. Sometimes our own government has even lied to us to generate fear and get the populace to back an action that would otherwise not be supported.
President Lyndon Johnson lied to America to get the country to support a much heavier military involvement in Vietnam. The "Battle of Tonkin Gulf" was the sole basis of the Tonkin Gulf Resolution. The "battle" never actually happened. On the evening after the battle that didn't actually happen (August 4, 1964), President Johnson went on TV to ask the country to support a Congressional resolution. Two days later the Tonkin Gulf Resolution was approved. Over 50,000 Americans died in the Vietnam War. Years later we finally learned the truth.
Going back now to Pearl Harbor, some believe that President Franklin Roosevelt had prior knowledge of the attacks. I only recently heard this accusation (from various sources), and I have no idea if it's true. What concerns me, however, is that I would not be surprised if it were proven that FDR mislead America in order to bolster support for involvement in the Pacific in WWII.
The reason I would not be surprised is that we know that Johnson lied to us. We know that Nixon lied. There is evidence that FDR may have lied. And we now know that George W Bush lied about at least some aspects of the Iraq situation.
On the really scary end, I've seen articles and videos by folks claiming that the Bush Administration not only lied about the WMDs in Iraq (as we know now), and deliberately misled the country to try and get us to believe that Saddam was somehow connected to the attacks of Sept 11, 2001 ....but these folks also believe that the Bush group had prior knowledge of the attacks, and did nothing. Some go even further with their allegations. I'm not going to get into that here; you can go to Google and search on "911 coverup" or "911 conspiracy" and read all kinds of stuff. You can also check out the 911 In Plane Site video - previews and comments are at the linked site. I've purchased the video and it does raise a number of questions. I suggest trying to verify sources before believing everything. Remember that our government has lied to us in the past, the media has at best distorted some things in the past, and anyone can post anything on the Internet (including me, so do your own research!)
At this point we really don't know what the whole truth might be. But if al Qaeda was behind the 9/11 attacks, and if bin Laden was behind al Qaeda, and if bin Laden was in Afghanistan ...then why the heck did we suddenly shift the main focus to Iraq, where there was no tie to the 9/11 attacks, there were no WMDs, there was no bin Laden? Even if you want to buy the story that Saddam had to be removed because he was evil, why now all of a sudden? Why not finish the job in Afghanistan first? There is some logic missing here, and no matter how many times Bush, Cheney, et al, change their story it won't make sense until the truth is told.
By the way, as a great example of how the Bush Administration is trying to use September 11, 2001 to increase fear and get some support from the voting public, have a look and listen at this clip culled from the Republican convention.