Delaware Primary Woo Hoo!!! In the Delaware Republican US Senate primary Christine ODonnell is defeating Congressman Mike Castle by a 55% to 45% margin with 37% of the vote reporting. It will be difficult for Castle to reverse her lead. They are... The Associated Press reports that Christine ODonnell has pulled off an almost-surprising upset over Rep. Mike Castle in the Delaware Republican primary after receiving the conservative-coveted endorsement of Sarah Palin last week.