The Club for Growth is planning a letter writing campaign to reach out to Sen. Arlen Specter’s (D-Pa.) donors now that the Federal Election Commission has given them legal cover to do so. The FEC ruled Thursday in favor of the club’s request to contact Specter’s donors based on its public records. “Over the next month, we plan to contact all individuals who contributed to Senator Specter’s campaign this cycle,— Club for Growth Executive Director David Keating said in a statement. Keating said the Club intends to include a preprinted form letter and envelope addressed to Specter’s campaign with his letters. “Senator Specter continues to face doubts about his loyalties, and I expect many of his donors will want their money back,— Keating continued. “We hope to make it a little easier by informing them of the Senator’s policy and providing a preprinted letter and envelope to request a refund.—When Specter announced in April that he was switching parties to run for re-election as a Democrat, he promised to return any campaign contributions at his donors’ request. According to his second quarter fundraising report, Specter had returned $407,600 in campaign donations as of June 30. The 29-year incumbent reported having raised $9 million for his re-election at the end of March — about four weeks before he announced he was switching parties.Former Rep. Pat Toomey (R-Pa.), who is also the immediate past president of the Club for Growth, is running for the Republican Senate nod. Specter barely defeated Toomey in their 2004 GOP primary and early polls this year showed him badly trailing the former Congressman in tests of the 2010 GOP primary.And now that he is a Democrat, Specter is getting a primary challenge from Rep. Joe Sestak (D-Pa.). Sestak, a two-term Congressman from southeastern Pennsylvania, trails Specter in public primary polls by double digits.