Terrorists do pose a danger, no question. The serious matter at hand though is to what extent do we amend existing law to fight them. FISA dates back to the 1970's, so changes are in order (I think) to bring it current with technology. These matters are all things that should be debated and studied. The problem is, the Bush administration has taken it upon themselves to do whatever they want, with no authorization or oversight. That is unacceptable in a free society. I'm not even against monitoring calls between terrorists and nationals in the US... BUT, it is something that MUST BE CAREFULLY DONE WITH OVERSIGHT. It has to confine to the rule of law.
Lincoln had no "oversight" and neither did FDR nor Truman, in the way that you mean.