Rep. Mike Castle will not run a write-in campaign for Delaware’s open Senate seat, the Republican said in a statement Wednesday night.

“While I would have been honored to represent Delaware in the U.S. Senate, I do not believe that seeking office in this manner is in the best interest of all Delawareans. Therefore, it’s time for Jane and me to begin thinking about the next chapter of our lives,” he said, referring to his wife.

Castle lost the GOP primary this month to Christine O’Donnell, a favorite of the tea party movement. Castle was considered the stronger GOP candidate for the general election against Democrat Chris Coons, and a write-in bid by Castle likely would have siphoned off votes from Coons. Democrats are now favored to hold the seat formerly held by Vice President Joseph Biden.

Castle was first elected to the House in 1992 and has served nine terms. He had until Thursday afternoon to make a decision about a write-in campaign.

“Since the outcome of the Republican primary election for the United States Senate, many Delawareans have encouraged me to pursue the Senate seat as a write-in candidate for the general election in November. … Jane and I have been humbled by the strong encouragement from so many friends, colleagues and supporters to undertake this effort,” he said in the statement. He did not mention O’Donnell in the statement.