The nation's largest federal employee union sued the Obama administration on Friday, claiming that forcing some federal employees to work without pay during a government shutdown violates the U.S. Constitution.
The American Federation of Government Employees seeks an injunction to prevent the administration from requiring federal employees who are deemed essential to keep working if a shutdown occurs.
"Hundreds of thousands of federal employees will be required to work during a shutdown, and there's no guarantee that Congress will keep the administration's promise to pay those employees once the shutdown is over," said John Gage, the union's president.
A White House spokeswoman would not immediately comment on the lawsuit.
The lawsuit says requiring work without pay violates language in the Constitution that prohibits the government from committing to spend money that has not yet been approved by Congress.
It also claims forcing employees to work without pay violates the prohibition on involuntary servitude.
Congress and the White House face a deadline of midnight Friday to agree on funding to keep the government open.
Joe Henderson, an attorney representing the union, said no hearing has been set in the case. He said he did not expect a hearing to take place Friday.
The union, which represents about 625,000 government workers, filed a similar lawsuit during the last government shutdown of 1995-96, but the shutdown ended before a judge heard the case and was eventually dismissed, Henderson said.
The union's latest lawsuit, filed in U.S. District Court in Washington, names Office of Management and Budget Director Jacob Lew and Office of Personnel Management Director John Berry as defendants.
"The Constitution requires an appropriation by Congress before federal dollars can be spent, no exceptions," Gage said. "Without an appropriation, the agencies simply can't spend money or incur debts by forcing employees to work."