Yeah, this should convince that McCain supporter to vote for Obama:

At some point during the wee hours of the morning, supporters of opponent Barack Obama attacked a private home in Prince George’s County, Md., defacing the house, an RV, a truck cover, and a two foot by eight foot yard sign. Apparently, the home owner was a registered Democrat and the local Obama fans were none to pleased with his decision to back McCain.
“I understand that in every election there are incidents where campaign signs on both sides are removed, torn down and defaced,” said Mykel Harris, Republican Central Committee Chair for Prince George’s County in a statement to the media. “But rarely do the perpetrators proceed to deface your home and personal property in your yard.”