The U.S. will reach its $14.29 trillion legal debt limit no later than May 16 unless Congress acts before then, Treasury Secretary Timothy F. Geithner said.

The Treasury Department will turn to a toolkit of emergency measures that can provide up to Aug. 2 of additional borrowing room if the limit isn’t raised in the next two weeks, Geithner said today.

“Protecting America’s creditworthiness and our economic leadership position in the world is a duty to our country that is shared by policy makers in both parties, in the Legislative Branch as well as the Executive Branch,” Geithner said in a letter to Senate Majority Leader Harry Reid, a Nevada Democrat. “Therefore any attempt by either party to use the full faith and credit of the United States as a bargaining chip to advance partisan policy agendas would be irresponsible.”

President Barack Obama has offered the outlines of a plan to reduce the debt by $4 trillion over 12 years through a combination of spending cuts and tax increases. House Budget Committee Chairman Paul Ryan, a Wisconsin Republican, has proposed cutting spending by $6 trillion over a decade in part by privatizing Medicare and capping Medicaid spending.

Geithner last week urged Congress to act by June to raise the debt limit, saying it would be “irresponsible” and “unacceptable” not to do so. “The idea that the United States would take the risk people start to believe we won’t pay our bills is a ridiculous proposition,” he said.