Who will be the Iraq conflict's equivalent to Walter Cronkite?

There is a story oft told that Nixon said that he lost America on the issue of Vietnam the day Walter Cronkite turned against the war.

Which brings up an interesting question: is there any public figure in America today, of equivalent stature to "the most trusted man in America", who, if he/she were to turn against Dubya's little adventure in Iraq, would effectively spell the end of American support for said adventure?

I can't think of any. There just isn't anyone around today that is as trusted as Cronkite was. Such is the cynical nature of our society.

Update: I am informed by DaveH in the comments that it was LBJ, not Nixon, who made the comment about losing Cronkite. Thanks for the correction.