Be vigilant and do not trust the government to do the right thing. Be active, protest, make your voice heard. ALso, when the government is doing the right thing, make certain they know you agree.
You can trace the problems with 9/11 back to the Revolutionary War if we wanted to. At the very least, the blame flows back to Reagan, Bush, Bush, and Clinton. But there are always little tips and oments in time that tradegies could be avoided. Look at Pearl Harbor, we had messages of the Japanese planes heading our way and didn't believe them.