Spineless Congress vs. The Imperial Presidency

[Update: Turns out it is probably true after all, Specter's denial was a lie, if the markup copy of the legislation that Greenwald obtained is accurate.]

[Edit: It turns out the amnesty provision was not in fact in the bill. The Washington Post reported that it was. Glen Greenwald has a lengthy post explaining what happened.]

Glen Greenwald's blog has rapidly become one of the strongest voices criticising this administration, and those who carry water for it. His posts often have a depth and thoughtfulness that other blogs (including this one) ususally lack. In this post, "A new low", he outlines just how far congressional bootlicking of the Bush administration has gone:

But that complete change of heart by Specter is not even nearly the most corrupt part of his proposed bill. For pure corruption and constitutional abdication, nothing could match this:

Another part of the Specter bill would grant blanket amnesty to anyone who authorized warrantless surveillance under presidential authority, a provision that seems to ensure that no one would be held criminally liable if the current program is found illegal under present law.

Other bloggers link to this Greenwald post here (Taylor Marsh questioning just how godly Ann Coulter is) and here (digby urging Democrats to leap on this "amnesty" for both policy and political reasons).

What I don't get is this: Bush is a very unpopular president. Why is congress sucking up to him? Why aren't they trying to score political points by publicly rebuking the administration for its errors? Why aren't they hampering him at every turn? I can understand kow-towing to him when his approval is sky-high, immoral as that might be. But it is utterly incomprehensible to me that people feel they can't stick it to him when is approval is in the low-mid 30s. At those levels, even Republicans should be distancing themselves from him, both in word and deed.