Remember how the Democrats had Lautenberg replace “The Torch” in the race for the NJ Senate seat? It was even more of a naked political maneuvre, but the NJ voters bought it and voted for Lautenberg.
They’re targeting the “blue” states that are trending toward McCain - Michigan, Pennsylvania, Washington, Wisconsin, etc. Putting Hillary on the ticket, even at this late stage, would put those states safely back into the dark side. Those voters who would switch back to the Dems after this stunt would be voting for Hillary just as most of us are voting for Palin.