The Senate returns at 2 p.m., and will take up S.J.Res. 20, which authorizes the use of military force in Libya for up to one year.
The resolution is similar to a measure that failed in the House in June, although there are some differences.
Under the Senate bill, the use of force would be authorized for one year or until the end of the NATO mission in Libya, whichever comes first. The House bill authorized the use of force for one year.
Like the House bill, the Senate version opposes the use of ground troops in Libya.
A procedural vote on the Senate resolution is expected at 5 p.m. The Senate will hold a vote on whether it can take up the bill, which requires 60 votes to pass. The procedural vote is needed because Sen. Ron Johnson (R-Wis.) last week blocked a request to take up the measure; Johnson argued that the Senate should instead focus on resolving the fight over the debt ceiling.
Lawmakers in both parties have sparred with the administration over the Libya military mission. President Obama has argued the Libyan action does not require congressional authorization under the War Powers Resolution because U.S. actions do not meet the meaning of "hostilities" under that measure. The U.S. military is in a supporting role to NATO in Libya.
The House returns at 1 p.m. Tuesday, but just for a pro forma session; no votes are expected.
—This story was updated at 10:40 a.m. to add details about the vote.