ALBANY — State Senator Simcha Felder, a Democrat from Brooklyn, announced on Tuesday that he will continue to caucus with the Republicans, short-circuiting hopes of a new Democratic majority in Albany’s upper chamber.

Mr. Felder, who has repeatedly said he actually has no loyalty to any party, said in a statement that he would continue to sit with the Republican majority regardless of the outcome of two special elections being held in the Bronx and Westchester County.

If Democrats win both seats, the party would gain a numerical edge in the Senate, theoretically giving them control — but only if Mr. Felder returns to the fold. Instead, Mr. Felder said that he believed the issue would be “best resolved outside of the legislative session,” which ends in June.

“I believe it is my obligation to prevent an unprecedented and uncertain late-session political battle that will only hurt my constituents and New Yorkers,” Mr. Felder said. “Political gamesmanship must not be allowed to jeopardize the leadership, committee structure and staff of the New York State Senate and push this institution into turmoil.”