This is indefinite dictatorial power. And I don't use that term lightly; the very definition of a dictatorship is a system that puts a ruler above the law. In the weeks after 9/11, while America and the world were grieving, Bush built a legal rationale for a dictatorship. Then he immediately started using it to avoid the law.
This is, fundamentally, why this issue crossed political lines in Congress. If the president can ignore laws regulating surveillance and wiretapping, why is Congress bothering to debate reauthorizing certain provisions of the Patriot Act? Any debate over laws is predicated on the belief that the executive branch will follow the law.
This is not a partisan issue between Democrats and Republicans; it's a president unilaterally overriding the Fourth Amendment, Congress and the Supreme Court. Unchecked presidential power has nothing to do with how much you either love or hate George W. Bush. You have to imagine this power in the hands of the person you most don't want to see as president, whether it be Dick Cheney or Hillary Rodham Clinton, Michael Moore or Ann Coulter.
Bruce has a blog with more data on the subject.