A third Republican is reportedly filing to run for Rep. Carol Shea-Porter‘s (D-N.H.) seat, a move that further complicates the GOP’s chances of taking back the competitive 1st congressional district in 2010.

Businessman Richard Ashooh told the New Hampshire Union Leader today that he plans to file the appropriate paperwork with the Federal Election Commission this week to open an exploratory committee, but he will make a final decision about a bid in the first three months of 2010.

Ashooh is the third competitive GOP candidate to file for the seat, joining Manchester Mayor Frank Guinta and fellow businessman Bob Bestani in the race. A competitive September primary could be devastating to New Hampshire Republicans and the National Republican Congressional Committee, which recruited Guinta to run for the seat.