Party-switching Sen. Arlen Specter fell to a younger and far less experienced rival in the Pennsylvania Democratic primary, and political novice Rand Paul rode support from tea party activists to a Republican rout in Kentucky on Tuesday, the latest jolts to the political establishment in a tumultuous midterm election season.

In another race with national significance, Democrat Mark Critz won a special House election to fill out the term of the late Democratic Rep. John Murtha in southwestern Pennsylvania. The two political parties spent roughly $1 million apiece hoping to sway the outcome there, and highlighted the contest as a possible bellwether for the fall when all 435 House seats will be on the ballot.

On the busiest night of the primary season to date, Arkansas Democratic Sen. Blanche Lincoln was forced into a potentially debilitating runoff election against Lt. Gov. Bill Halter in her bid for nomination to a third term. The run-off will be June 8.

http://news.yahoo.com/s/ap/us_primary_rdp