WASHINGTON ― Republicans in the U.S. Senate last month did not oppose funding the government without giving President Donald Trump money for a border wall.

This month, they do.

The difference between then and now is that Trump has wholeheartedly embraced the concept of shutting down parts of the federal government to force congressional Democrats to support funding for the wall.

The reversal suggests that a funding bill similar to last month’s could pass in this Congress, too, but Senate Majority Leader Mitch McConnell (R-Ky.) refuses to allow a vote on any spending bill that does not have the support of the president.

It’s possible a bill to reopen the government could pass with enough support to override a presidential veto. But Republicans suggested Wednesday they wouldn’t dare.

“I’m going to defer to the president on the best strategy and I would never vote to override a veto on something that the president didn’t think was the best approach,” Sen. Thom Tillis (R-N.C.) told HuffPost while carrying a lapdog named Mitch to McConnell’s office on Wednesday.

Fun meeting Mitch Tillis, the newest addition to the Tillis family! #mitchmeetmitch pic.twitter.com/0g41vfh9kt — Leader McConnell (@senatemajldr) January 9, 2019

Other Republicans scoffed at the prospect of overriding a veto. Sen. Roy Blunt (R-Mo.), a member of GOP leadership, called the prospect of 20 Republicans joining all Democrats in bucking Trump over the wall “a waste of time,” adding that it would “never happen.”

But if this Congress worked as the founders intended ― as a branch of government that is equal to the White House ― lawmakers could at least be given a chance to vote on a bill to reopen the government ― especially one they already passed less than a month ago.

“The Constitution doesn’t make Congress subservient to the president,” Sen. Chris Murphy (D-Conn.) said. “No one here has to follow the order of President Trump, especially when he’s doing something bad for the country.”

The funding bill that the Senate passed in December ― which would have kept the government operating until February but did not include any wall money ― passed easily, without a roll call vote, meaning zero out of 100 senators opposed it strongly enough to demand a roll call. Any Republican senator currently repeating the Trump administration’s line about a “crisis” on the U.S.-Mexico border could have forced a recorded vote on the measure over its lack of border security funding, but none did.

Sen. Jerry Moran (R-Kansas) said Wednesday that he was one of two senators who said “no” to the December funding bill on the Senate floor during the voice vote. The Appropriations Committee member did so, he said, because of a general objection to funding government via a short-term “continuing resolution” ― not the fact that it contained no funds for Trump’s wall.

“I keep telling myself I’m never voting for a CR again,” Moran told HuffPost.

Before the Senate agreed to the resolution, McConnell said Republicans would “fulfill our duty to govern” even though Democrats were being intransigent about funding Trump’s border wall (which, after all, the president had previously said would be funded by Mexico, not Congress).

But then the House of Representatives, which was still under Republican control at the time, refused to hold a vote on the Senate bill because Trump had belatedly decided he opposed it, contrary to previous signals from the White House. The new Democratic House has approved funding but couldn’t send the previously passed Senate measure to the president without the Senate passing it again.

The Constitution doesn’t make Congress subservient to the president. No one here has to follow the order of President Trump. Sen. Chris Murphy (D-Conn.)

The government has been shut down since Dec. 21, and the consequences are mounting. A range of services, including trash pickup in national parks, have ceased. This week, some 800,000 federal workers will start missing paychecks. The Internal Revenue Service announced an ad hoc plan to pay tax refunds, and the U.S. Department of Agriculture said it could pay food benefits for February but not necessarily March.

Trump repeated Wednesday that the shutdown could continue “for as long as it takes,” raising the possibility that his push for a border wall could result in mass hunger for the 38 million Americans who currently receive food benefits each month.

Nevertheless, a funding bill that didn’t include money for Trump’s wall would not succeed now, Sen. John Cornyn (R-Texas) said.

“What we need is a negotiated outcome, not trying to vanquish your political foes, which is the exercise we’re engaged in right now,” Cornyn said.

HuffPost pointed out to Cornyn that Congress and the White House are coequal branches of government and that lawmakers could override a presidential veto.

“With 67 votes,” Cornyn said, implying that the higher vote threshold for a veto override would be unreachable.

While presidential veto overrides are rare, they have occurred many times in history. Most recently, Congress voted overwhelmingly to override President Barack Obama’s veto of a bill that allowed families of the victims of the Sept. 11, 2001, attacks to sue the government of Saudi Arabia.

Sen. Patrick Leahy (D-V.t.), the top Democrat on the Senate Appropriations Committee, predicted that a bill funding the government that did not include money for a wall would pass “overwhelmingly” if it was allowed to come to the floor.

“Every Republican will tell you that privately,” Leahy told HuffPost on Wednesday.

Still, there are no signs that Republican leaders are planning on backing down.

Trump visited Capitol Hill on Wednesday to reassure uneasy rank-and-file members and urge them to stand firm as the shutdown barrels toward its fourth week. Several moderates ― including Lisa Murkowski of Alaska, Susan Collins of Maine and Cory Gardner of Colorado ― have called for votes to reopen most of the government without a resolution on the wall funding.

But some of the president’s biggest allies in Congress say the issue of the wall is a life-and-death situation for the Trump administration ― and maybe even the Republican Party writ large.

“If we undercut the president, that’s the end of his presidency and the end of our party,” Sen. Lindsey Graham (R-S.C.) said Tuesday in an interview on Fox News.