A New York Times editorial lays it on the line:
Mr. Bush, however, seems to see no limit to his imperial presidency. First, he issued a constitutionally ludicrous “signing statement” on the McCain bill. The message: Whatever Congress intended the law to say, he intended to ignore it on the pretext the commander in chief is above the law. That twisted reasoning is what led to the legalized torture policies, not to mention the domestic spying program.
Then Mr. Bush went after the judiciary, scrapping the Levin-Graham bargain. […]
Both of the offensive theories at work here – that a president’s intent in signing a bill trumps the intent of Congress in writing it, and that a president can claim power without restriction or supervision by the courts or Congress – are pet theories of Judge Samuel Alito, the man Mr. Bush chose to tilt the Supreme Court to the right.
The administration’s behavior shows how high and immediate the stakes are in the Alito nomination, and how urgent it is for Congress to curtail Mr. Bush’s expansion of power. Nothing in the national consensus to combat terrorism after 9/11 envisioned the unilateral rewriting of more than 200 years of tradition and law by one president embarked on an ideological crusade.
[via Daily Kos]