Potential 2010 Senate candidate Pat ToomeyPatrick (Pat) Joseph ToomeyNewly declassified memos detail extent of improper Obama-era NSA spying Overnight Tech: FCC won't fine Colbert over Trump joke | Trump budget slashes science funding | Net neutrality comment period opens Appeals court decision keeps lawsuit against NSA surveillance alive MORE will make an appearance at a key conservative activists' dinner tonight, perhaps laying groundwork for a campaign.

Toomey will be the keynote speaker at the Pennsylvania Leadership Conference taking place in Harrisburg, Pa. this weekend.

The conference will host what it asserts on its website is a record number of conference attendees in central Pennsylvania, as Toomey mulls a primary challenge to Sen. Arlen Specter (R-Pa.).

Toomey had challenged Specter from the right in 2004, and would again wage a conservative challenge should he run again.