The Club For Growth is looking to employ a fun new tactic against their long-time nemesis, Sen. Arlen Specter (R-turned-D-PA), and has sent a letter to the FEC asking permission for this novel maneuver: To send a mass mailing to previous Specter donors, reminding them of the incumbent's offer to return donations to anyone who asks, and including a form to help them do just that!
The Club, of course, previously bankrolled then-Rep. Pat Toomey's conservative primary challenge against Specter in 2004, which Specter just barely won by 51%-49%. Toomey became the Club's president some time afterward, then left to challenge Specter again in 2010 with the group's full backing. This then led to Specter's party switch, and he singled them out for condemnation during his press conference announcing his move.
The Club's letter to the FEC includes their arguments for why they believe this action by them is permitted under the law, along with various disclaimers -- that Specter is not legally required to return donations and their own letter would remind recipients of this, that they would not broker any mailing lists from this, that they won't solicit recipients for any donations to the Club or another candidate, etc.
Bottom line: Assuming this is legal, the Club has found yet another way to annoy Specter.