What will Kagan do about the "Unitary Executive"?

What do you make of this NYTimes OpEd? John Yu is the White House Counsel who gave Bush the answer he wanted to hear when asked to write a memo on torture. Now he argues that Kagan (on the Supreme Court) might try to roll back some of the dictatorial powers arrogated to the President. This is the opposite of what Greenwald has written: http://tinyurl.com/y7pmvcd