After insisting for a year that failure was not an option, President Barack Obama is now acknowledging his health care overhaul may die in the US Congress. His tone at a Democratic National Committee fundraiser yesterday night verged at times on defeatist. Even while saying he still wanted to get the job done, Mr. Obama bowed to new political realities. Democrats no longer command a supermajority in the Senate, and voters and lawmakers are far more concerned with jobs and the economy than with enacting sweeping and expensive changes to the health system. Sweeping health legislation to extend medical coverage to more than 30 million uninsured Americans passed both chambers of Congress last year and was on the verge of completion before Republican Scott Brown's upset victory in a Massachusetts special Senate election last month. Mr. Brown was sworn in yesterday, giving Republicans 41 votes, enough to block the initiatives of the 59-seat Democratic majority. Now the health legislation hangs in limbo. Lawmakers are looking to Mr. Obama for guidance, but he has not publicly offered specifics. His signals have been mixed.