This is perhaps stating the obvious, but I want to come out and say it explicitly: Republicans hate the law.
The Yoo "Torture Memo" is just the latest and most dramatic example of the Bush administration’s adversarial relationship with the law and the Constitution. Republicans don’t see the law as the foundation of a healthy nation, to be upheld and protected, they see it as an obstacle – to be evaded, ignored, twisted, and exploited.
The Bush administration didn’t just use John Yoo’s memo to justify torture in violation of the Geneva Conventions and the Bill of Rights – they pressured Congress to legalize it and to suspend habeas corpus. They ignored FISA, then pressured Congress to make their warrantless wiretapping legal and grant their teleccomplices retroactive immunity.
They used the DOJ to slow-walk investigations of corrupt Republicans (wasn’t Jack Abramoff supposed to sing like a canary?) and to prosecute Democrats like Georgia Thompson, Don Siegelman, and possibly Eliot Spitzer. They even used it to prosecute the Qwest CEO who refused to help them violate FISA. They pressured US Attorneys to trump up voter fraud cases so they could push "voter reform" which would disenfranchise minorities. US Attorneys who wouldn’t go along with the program were fired.
Dubya used signing statements to exempt himself from laws which might constrain his executive powers. The White House used "executive privilege" to stonewall congressional oversight of the US Attorney firings, even when the president supposedly wasn’t involved. And the Republican nominee, Straight-Talking Man Of Integrity John McCain, is in violation of campaign finance law every single day.
I’m sure I’ve left out countless examples, but I think you get the idea. Republicans in general, and the Bush administration in particular, simply cannot stand to be bound by the law. It chafes them, it burns them, and they must defeat it and subjugate it at any cost, even if that cost is democracy itself.