Why is it?

That when John Kerry "changes his opinion as reasonable people do" its called flip flopping.

Yet if Kate O' Bierne does it, it goes unchallenged?:

"According to the two transcripts Drudge has posted, Harriet Miers was a critic of the Federalist Society before she became one of its biggest fans. She changed her opinion as reasonable people do - but wait. The President tells us that she is the kind of person who will never, ever change. This gets very confusing. I'm not surprised that this year found Miss Miers praising the Federalist Society - that is the view of her boss. Do powerful people ever notice that the people in their employ agree with them an extraordinary amount of the time? Funny how that works"

Amazing! So Harriet Miers is a reasonable person for flip flopping?