Kill the PATRIOT Act

In the days after 9/11, Congress understandably passed the PATRIOT Act, a sweeping piece of legislation that pruported to allow our law enforcement officers to more effectively investigate and catch terrorists before they strike. As I say, this was completely understandable at the time. We were scared, and we didn't want it to happen again. The FBI and other agencies said that they needed these expanded powers, and we trusted that they were telling the truth and they actually did. Knowing what we know now though, why is Congress even considering renewing these powers?
We now know that the FBI knew that "Middle Eastern men" were interested in learning to fly big planes, but not necessarily how to land them, but this information was never acted upon. We also know that the "Able Danger" team had identified Mohammad Atta and three other 9/11 hijackers by mid-2000 but were prevented by military lawyers from giving this information to the FBI. Even the 9/11 Commission that was created to uncover what was known about the attacks has ignored the "Able Danger" findings.
Knowing all these facts, why is Congress even considering renewing the expanded powers that law enforcement claimed they needed? They had the information they needed and were unable to do anything about the attacks. What makes us think that they would be more competent if they kept the expanded powers? The worst part is that the law as it exists now says that the FBI doesn't even have to tell us what they're using the powers for, or if they are effective. Indeed, we often end up getting more scared at the vague terror alerts that shut down our subways or tunnels. Thankfully, a small group of legislators seems to realize that these expanded powers should not be given out willy-nilly, and are standing up to try to change the legislation. We can only hope they succeed.