Choosing Sarah Palin as his running mate was apparently meant to accomplish the following:

# Rally the conservative base without alienating the center. # Increase support among white women, many of whom may have been disappointed by Senator Clinton's loss # Defend against Obama's framing himself as the Change candidate and McCain as a third term of George W Bush. Reposition the campaign with McCain and Palin as the Reformers and Obama / Biden as the Establishment. # Generate a lot of excitement and press coverage. He seems to have succeeded in all of these points.