WASHINGTON — Congress is poised for another partisan showdown over extending unemployment insurance, as concerns about the growing budget deficit have complicated the path forward for an otherwise popular program.

On its first day back in session after a two-week recess, the Senate is scheduled to vote today on whether to end debate on a measure extending jobless benefits, subsidies for the COBRA health insurance program and federal flood insurance through May 5. Democrats will need at least one Republican supporter to get the 60 votes necessary to proceed.

The Senate failed to agree on the bill in late March, after Republicans rejected an attempt to expedite the measure’s passage. Because of the impasse, beginning April 5 more than 200,000 unemployed people who had already exhausted their states’ jobless benefits could not apply for additional benefits from the federal program, according to estimates by the National Employment Law Project, a liberal advocacy group.

Each party has blamed the other for the cutoff. Democrats point out that they easily moved an extension through the House and were primed to do the same in the Senate before Republicans, led by Sen. Tom Coburn, R-Okla., stood in the way.

Republicans respond that they’re not opposed to extending unemployment benefits but want to offset the $9 billion cost with spending cuts elsewhere.

“We both want to extend unemployment benefits,” said Sen. Lamar Alexander, R-Tenn., the GOP’s No. 3 leader. “The Democrats want to do it by adding to the debt. Republicans don’t want to add to the debt.”

Sen. Jim Bunning, R-Ky., made the same argument when he led the GOP’s stand against a previous extenders package at the beginning of March. That blockade lasted five days and drew national press attention, much of it unfavorable to Bunning and his party.

Then, many Republicans were privately critical of Bunning’s tactics and fearful of being tarred as unsympathetic to the jobless. Now, Republicans are largely united in their stand, and the vast majority are expected to vote today against moving forward on the extensions.