(CNN) - Rep. Peter King is formally bowing out of this year's New York Senate contest, again.
"While the political situation has changed dramatically in the Republicans' favor since September and I believe that Sen. (Kirsten) Gillibrand can and will be defeated in 2010, I will not be a candidate for the Senate," he said in a message sent to supporters Monday.
The 9-term Long Island Republican had announced his decision to skip the race last fall, but said in December that he would reconsider his decision based after requests by party leaders. He claimed the national spotlight in recent weeks as one of the most vocal congressional critics of the White House's response to the attempted Christmas Day airline bombing.
Surveys indicate Gillibrand could be vulnerable in a battle with a strong opponent. In a Siena poll last month, just under a third of the New York voters questioned thought she deserved to hold on to her seat, and 34 percent said they'd back another candidate. In the same poll, Gillibrand was virtually neck-and-neck with George Pataki, with a 46-43 edge over the former GOP governor.
In his Monday message, King cited the time demands of fundraising and campaigning, a reason he has cited in the past. He also repeated that he was "increasingly confident" the GOP would take back Congress, giving him the change to reclaim the chairmanship of the Homeland Security Committee.
Last month, former New York City mayor Rudy Giuliani opted out of the state's 2010 races for governor and senator. King's decision again deprives Republicans of another of the party's most high-profile potential Senate contenders.