Longtime Rep. Mike Castle (R-Del.) announced late Wednesday that he will not launch a write-in bid for Senate this fall, ceding the stage to Tea Party favorite Christine O'Donnell (R) and New Castle County Executive Chris CoonsChris CoonsOvernight Healthcare: McConnell unveils new Zika package | Manchin defends daughter on EpiPens | Bill includes M for opioid crisis Dems to GOP: Help us fix ObamaCare Cruz fights domain name handover in hearing MORE (D).
Castle said he was "humbled" by the support and encouragement he has received since his primary loss to O'Donnell, but after giving a write-in bid careful consideration, he decided against it.
Castle's announcement ended a week of speculation that the centrist Republican would follow in the footsteps of Sen. Lisa MurkowskiLisa MurkowskiOvernight Energy: Obama integrates climate change into national security planning GOP pressures Kerry on Russia's use of Iranian airbase Overnight Energy: Lawmakers kick off energy bill talks MORE (R-Alaska) and create another three-way Senate race after suffering a primary upset at the hands of a Tea Party-backed candidate.
Castle, who lost to conservative commentator Christine O'Donnell in the state's GOP primary, told reporters last week that he was considering a write-in campaign this fall. The congressman would have had to declare his intention to run as a write-in candidate by Thursday.
In the statement, Castle makes no mention of Christine O'Donnell, who he declined to endorse after the primary.
"I've been just sort of trying to come to final closure," Castle told The Hill Wednesday afternoon before he officially announced his decision to not forge ahead with a write-in bid.
The longtime congressman didn't shed too much light on his decision making process Wednesday, but did say "it's been more of an evolution over the past couple of days."
A write-in bid would have been an uphill battle for Castle and a Rasmussen poll from earlier in the week suggested such an effort might have only given O'Donnell a better shot at defeating Coons in November. The poll had Coons ahead of O'Donnell 49-40 percent with Castle garnering 5 percent as a write-in.