Aides say test vote likely will help show House Democrats the Senate cannot pass the wartime supplemental with extra domestic spending tacked on.
The Senate is on course to vote on a House-passed fiscal 2010 supplemental spending bill, even as House Democrats appear to be moving to eventually accept a Senate measure without domestic spending Democrats in the lower chamber want.
The Senate could hold a cloture vote on the House-passed measure this week, Democratic leadership aides said, though next week may be more likely. Democrats expect that cloture vote to fall short and say the House will eventually have to accept that a bill without the added domestic money is all the Senate can pass.
"They have no choice," a spokesman for Senate Majority Leader Harry Reid, D-Nev., said of the House agreeing to a bill without the added money.
After Senate passed a $59 billion version of the measure in May, the House added what the House Appropriations Committee said is $22.8 billion in domestic spending including funds to prevent teacher layoffs.
The White House has threatened to veto that bill over a pay-for rescinding money for the administration's "Race to the Top" grant program for schools.
Though House Democrats note the spending is paid for, Senate Republicans say they will oppose the bill over the additional spending, leading to Democrats' expected loss on the cloture vote. Several aides said the test vote would help show the House Democrats the Senate cannot pass the broader House measure and would allow Democrats to fault Republicans for blocking it.
A Democratic leadership aide said that if the vote fails "we will have to negotiate with Republicans to see what they will accept to get the needed 60 votes."
Top House Democrats Monday appeared increasingly to accept the likelihood of the Senate approving a "clean" bill as both chambers considered other ways to pass the domestic spending, all of which appear tough to pull off.
When House Armed Services Committee Chairman Rep. Ike Skelton, D-Mo., on Monday suggested Reid schedule a vote soon on a "bipartisan" measure that can pass, he appeared to break with top House Democrats including Speaker Rep. Nancy Pelosi, D-Calif., and Appropriations Committee Chairman Rep. David Obey, D-Wis., who have prioritized the domestic spending.
"I am writing to respectfully request that you schedule a vote at the earliest possible opportunity on a Fiscal Year 2010 Supplemental Appropriations bill containing at least $37 billion for overseas contingency operations of the Department of Defense," Skelton wrote in a letter.
Skelton wants the Senate to vote on such a "clean" bill, one Democratic aide said.
Skelton urged "that the bill be constructed so that it can obtain broad bipartisan support in the United States Senate. The long-standing tradition of bipartisan support of the Armed Forces in times of war should continue to be our guide in this most critical of times for national security, and particularly in this critical hour for our ongoing operations in Afghanistan."
A Reid spokeswoman said he "shares Chairman Skelton's eagerness to get this bill to the president, and took swift action earlier to pass the bill before the House decided to broaden its scope. We plan to take up the bill again later this week, and continue to hope that, with the help of the House, we can get it done quickly."
Defense Secretary Robert Gates has also urged quick Senate action on the bill, and the Pentagon has developed a contingency plan in case Congress does not pass the supplemental before the August recess.
Humberto Sanchez contributed to this report.