WASHINGTON (AP) — President Barack Obama's top Democratic allies in the Senate are urging him to consider "any lawful steps" to make sure the government does not default of its debts and spur an economic crisis — even if it means acting without approval by Congress.

At issue is whether the Constitution permits the president to ignore the $16.4 trillion cap on government debt under the 14th Amendment. It states, in part, that the "validity of the public debt of the United States ... shall not be questioned."

The White House has said emphatically that it does not believe that the 14th Amendment permits Obama to ignore the debt cap on U.S. borrowing. The government reached that cap last month and is juggling the books to buy additional time for Congress to act.