It's been a tough day for him. His own party is now saying he made a wrong decision in his pick for VP:

From Sen. Chuck Hagel (R - Nebraska)In the interview, Hagel strongly criticized Palin's lack of foreign policy credentials and called her suggestion that the view of Russia from her home qualifies as international experience "insulting to the American people." From HERE.

McCain also said if he was president he'd fire the head of the SEC, which NO president can do!

And, Elizabeth Drew, a biographer of his, a great admirer at one point, has a lengthy article on how he lost her. You may read it HERE. It ends with this:

McCain's recent conduct of his campaign – his willingness to lie repeatedly (including in his acceptance speech) and to play Russian roulette with the vice-presidency, in order to fulfill his long-held ambition – has reinforced my earlier, and growing, sense that John McCain is not a principled man.
In fact, it's not clear who he is.