The US Senate finds itself on Friday in a familiar position, working to avoid a partial government shutdown with just hours to spare as Democrats confront two painful options: allowing passage of a bill they believe gives President Donald Trump vast discretion on spending decisions or voting no and letting a funding lapse ensue.

Senate Democratic leader Chuck Schumer gave members of his caucus days to vent their frustration about the options before them, but late on Thursday made clear he will not allow a shutdown. His move gives Democrats room to side with Republicans and allow the continuing resolution, often described as a CR, to come up for a vote as soon as Friday.

A procedural vote on Friday will provide a first test of whether the package has the 60 votes needed to advance, ahead of final voting likely later in the day. At least eight Democrats will need to join with Republicans to move the funding package forward.

“While the CR still is very bad, the potential for a shutdown has consequences for America that are much, much worse,” Schumer said.

Congress has been unable to pass the annual appropriations bills designed to fund the government, so they've resorted to passing short-term extensions instead. The legislation before the Senate marks the third such continuing resolution for the current fiscal year, now nearly half over.

The legislation would fund the federal government through the end of September. It would trim non-defense spending by about US$13 billion from the previous year and increase defense spending by about US$6 billion, which are marginal changes when talking about a topline spending level of nearly US$1.7 trillion.

The Republican-led House passed the spending bill on Tuesday and then adjourned. The move left senators with a decision to either take it or leave it. And while Democrats have been pushing for a vote on a fourth short-term extension, GOP leadership made clear that option was a non-starter. (AP)