Updated 4:29 p.m. | The Senate is “highly unlikely” to return Sunday to take up an amended House continuing resolution, according to a senior Senate Democratic aide. But whether the chamber comes back on Sunday or Monday, its message will be the same.

The proposal to delay implementation of the 2010 health care overhaul is a non-starter with Senate Democrats, as Majority Leader Harry Reid reiterated in a statement Saturday afternoon.

“Today’s vote by House Republicans is pointless. As I have said repeatedly, the Senate will reject any Republican attempt to force changes to the Affordable Care Act through a mandatory government funding bill or the debt ceiling. Furthermore, President Obama has stated that he would veto such measures if they ever reached his desk.

“To be absolutely clear, the Senate will reject both the one-year delay of the Affordable Care Act and the repeal of the medical device tax. After weeks of futile political games from Republicans, we are still at square one: Republicans must decide whether to pass the Senate’s clean CR, or force a Republican government shutdown.

“Senate Democrats have shown that we are willing to debate and vote on a wide range of issues, including efforts to improve the Affordable Care Act. We continue to be willing to debate these issues in a calm and rational atmosphere. But the American people will not be extorted by Tea Party anarchists.”

“That’s bullshit.”

Since the House has announced plans to move forward with attaching Obamacare delay language to the Senate’s stopgap spending measure, it appears that time has already run out to avert a government shutdown — absent unanimous consent in the Senate, of course

Regardless of when the Senate returns, it would be difficult for the chamber to do anything other than reject the House changes before midnight on Monday. Actually amending the House measure would require at least one, possibly more, debatable motions — a situation that would allow a filibuster. Any attempt to block could take three days or more to overcome.

The people most likely to attempt to delay action — GOP Sens. Ted Cruz of Texas and Mike Lee of Utah — had urged their House counterparts to return the “clean” Senate bill with more Obamacare language. But an email to Cruz’s office Saturday asking whether the tea party darling might try to object to any further attempts by Reid to change the House language was not immediately returned.

Reid could try to seek unanimous consent to disagree with the House amendments and dare Republicans to object hours from a shutdown, or the Nevada Democrat could move to table a motion to concur with the amendments. That would only require Democratic votes, and Cruz and Lee could not prevent those non-debatable motions from being brought up.

There’s also no technical reason the Senate has to hold any formal votes on the measure at all.

The Senate’s rules do not require the question of delaying Obamacare for a year to be considered separately from the medical device tax repeal amendment that the House Republicans also plans to send across the Capitol. The Congressional Research Service has a detailed explanation of the often confusing process through which the House and Senate exchange amendments without using a conference committee.

According to that CRS report: “The Senate … does not necessarily need to agree to a separate motion to dispose of each amendment. Instead, the Senate can agree to one motion to dispose of several House amendments, as long as the Senate is agreeing to dispose of them in all the same way.”

Back in 2010, when Democrats controlled the House, the Senate decided against invoking cloture on a war supplemental that included extra domestic spending. As part of a unanimous consent agreement, rejecting that motion to limit debate caused the Senate to automatically transmit a message back to the House that the Senate disagreed with the House amendment. The House ultimately accepted the Senate’s roughly $60 billion package.

“House Republicans are now actively pushing for a completely unnecessary government shutdown. Democrats and Republicans acted responsibly in the Senate to pass a clean short-term spending bill to prevent a government shutdown,” Senate Budget Chairwoman Patty Murray of Washington said in a statement Saturday. “I urge Republicans in the House to stop playing political games and pass the Senate’s short-term shutdown-prevention bill so the families and communities we represent don’t end up paying the price.”

She is also a member of the Democratic leadership team.

That’s not to say unanimous consent is impossible. In April 2011, a last-second deal on a spending package allowed Reid to get a short-term continuing resolution through after 11 p.m. one night.

The House didn’t actually clear that measure until after the midnight hour, when the shutdown was set to begin, but the Office of Management and Budget told departments and agencies to continue as normal, knowing the deal would be completed. The difference may be that in that case, a broader spending deal was at hand.

And while a Sunday session is unlikely, Sen. Benjamin L. Cardin, D-Md., told reporters Friday that senators were advised not to travel too far from Washington, D.C., this weekend, given the possibility that the schedule could change. Officially, the Senate’s set to return for regularly-scheduled morning business at 2 p.m. on Monday.

The Senate passed a continuing resolution Friday that would run through Nov. 15, rejecting the House’s earlier move to defund Obamacare.