Journalists like politicians that make them feel smart

It makes sense. Bush II isn't as dumb as he acts (he doesn't have that excuse), but he seems dumb to journalists. They feel good about that.

McCain, even without dementia, has the same feature.

Grasping Reality with Both Hands: The Semi-Daily Journal Economist Brad DeLong

...The number of mulligans that America's press corps gives John McCain is truly remarkable. I'm becoming increasingly convinced that it's because he doesn't threaten them--just as George W. Bush doesn't threaten them. By contrast, Bill Clinton and Al Gore and John Kerry and John Edwards and Hillary Rodham Clinton and Barack Obama are scary-smart, in the way that my ex-boss Alicia Munnell once spoke of Lloyd Bentsen: 'It only takes fifteen minutes before it is very clear why he is the Secretary of the Treasury and I am the Assistant Secretary.' That seems to provoke a reaction from many journalists...