An Interesting Contrast:
One more thought on John Yoo's op-ed. It's interesting to contrast Yoo's comment about the Bush Administration's view of the Executive power with what he wrote a few years ago about the Clinton Administration's view of Executive power. Here is Yoo today:
A reinvigorated presidency enrages President Bush’s critics, who seem to believe that the Constitution created a system of judicial or congressional supremacy. Perhaps this is to be expected of the generation of legislators that views the presidency through the lens of Vietnam and Watergate. . . .

The changes of the 1970’s occurred largely because we had no serious national security threats to United States soil, but plenty of paranoia in the wake of Richard Nixon’s use of national security agencies to spy on political opponents. Congress enacted the War Powers Resolution, which purports to cut off presidential uses of force abroad after 60 days. It passed the Budget and Impoundment Act to eliminate the modest presidential power to rein in wasteful spending. The Foreign Intelligence and Surveillance Act required the government to get a warrant from a special court to conduct wiretapping for national security reasons.

These statutes have produced little but dysfunction, from flouting of the war powers law, to ever-higher pork barrel spending, to the wall between intelligence and law enforcement that contributed to our failure to stop the 9/11 attacks.
Contrast this with what Yoo wrote back in 2000 on the Clinton Administration's approach to executive power, as I blogged about back in February:
President Clinton exercised the powers of the imperial presidency to the utmost in the area in which those powers are already at their height — in our dealings with foreign nations. Unfortunately, the record of the administration has not been a happy one, in light of its costs to the Constitution and the American legal system. On a series of different international relations matters, such as war, international institutions, and treaties, President Clinton has accelerated the disturbing trends in foreign policy that undermine notions of democratic accountability and respect for the rule of law.
Source: John C. Yoo, The Imperial President Abroad, in Roger Pilon, ed., The Rule of Law in the Wake of Clinton 159 (2000).

  To be fair, in the 2000 essay Yoo suggests that he himself favors a strong executive, such that having an "imperial presidency" isn't all that bad. But I think it's interesting that in 2000, Yoo thought that President Clinton was "exercis[ing] the powers of the imperial presidency to the utmost," with the resulting "costs to the Constitution," whereas today he seems to lament that before Bush the Presidency was excessively weak and not playing its proper strong constitiutional role. Am I missing something, or are these statements diametrically opposed to each other?