Rather, it is worth recognizing Bush's veto-- and indeed, many other future actions and acts of intransigence-- as part of an endgame strategy. At this point in Bush's Presidency he deals from a position of weakness, not strength. His major goals are to prevent criminal prosecutions of himself (unlikely in any event) and his aides (more likely), to keep the public from finding out much of what he and his advisors actually did and ordered done during his presidency (his fight for immunity for telecom companies who engaged in illegal surveillance should be understood as part of this larger strategy), to entrench the U.S. presence in Iraq for the foreseeable future, and do what he can to ensure that John McCain becomes President, or failing that, Hillary Clinton as a second best solution. He figures that McCain, and, to a lesser extent Clinton, are most likely to continue aspects of his policies and keep troops in Iraq for some time. The longer that the next president continues his policies-- including warrantless surveillance, his interrogation practices, and his war in Iraq, the longer these features will become normalized and/or the next President's problem.
What Bush does not want, above all, is to be followed by a repudiationist or reconstructive Presidency that establishes a new political order through systematic rejection of the themes of his Presidency, thus making Bush the modern day equivalent of Herbert Hoover and Jimmy Carter rather than Harry Truman. Bush's presidency is a failed presidency; the only issue now is how badly he has failed.
He has failed as badly as it is humanly (?) possible to fail and then some, period. Every incompetent and criminal act was done on purpose. Worst. President. Ever.
The next President, the first real one in eight years, absolutely must institute "systematic rejection of the themes of his Presidency". Posthaste with a hard-on.