Sen. Arlen Specter (R-Pa.) has his first official challenger for the 2010 election.

Democrat Joe Torsella, the former president of the National Constitution Center in Philadelphia, issued a press release Monday announcing that he had filed the appropriate federal paperwork to run for Senate in Pennsylvania next year.

Torsella lost a 2004 Democratic primary to now-Rep. Allyson Schwartz (D), who is also considering a Senate bid. Torsella currently serves as chairman of the State Board of Education.

Specter is expected to run for a sixth term in the Keystone State. He won re-election in 2004 over then-Rep. Joe Hoeffel (D-Pa.) after surviving a primary challenge from then-Rep. Pat Toomey (R-Pa.).

Democrats view Specter as a top target in 2010. He also faces the prospect of another competitive primary challenge.