When the base falls through
Rove's strategy was to get the base out this election. He spoke about it at length. If that is true, why would Bush be trying to "reach out across party lines" to get Democrats to vote for him as well? I would think that was a moment when you could tell they knew things were going poorly, or at least not well enough to win.
And of course, the longer the lines, the bigger the victory for John Kerry.
So of course, Get Out the Vote.