By Jordain Carney, The Hill–

Republicans are going down to the wire as they try to find a way out of their showdown with President Trump over his national emergency to build a wall on the Mexican border.

Republicans have just days to find a more palatable solution than the House-passed resolution blocking Trump’s actions, which is expected to come up for a vote by Friday.

They are looking for ways that Trump could win more wall funding without using the emergency declaration, a controversial move that has caused angst on Capitol Hill.

“I think we’re universally for what the president wants to do, but there’s significant concern about using the emergency in this new way that sets a precedent likely in court that future presidents could use,” said Sen. Roy Blunt (R-Mo.), a member of GOP leadership.

Without an off ramp, the resolution of disapproval has enough votes to pass the Senate, and as many as 15 Republicans could vote for it. That would be an embarrassingly high number for the White House, even if a Trump veto cannot be overridden.

Republicans have yet to find a plan that unites the caucus and passes procedural muster with the parliamentarian.

“My sense was we were kind of down to Plan Z. Started with Plan A and found that none of those worked,” Blunt said.

Sen. John Thune (R-S.D.), the No. 2 Senate Republican, said “the marketplace of ideas is percolating,” while Sen. John Cornyn (R-Texas) told CNN that there were “great ideas but no conclusions.”

The talks have ranged from amending the resolution to passing a separate stand-alone measure. Leadership staffers have been deputized to scour the chamber’s rules for help.

Sen. James Lankford (R-Okla.), who is undecided on the vote, said the parliamentarian has given them an initial determination that the House-passed resolution could be amended.

“That is the debate right now, what the amendment should look like, if we should have one,” he said. “All the options are out there on the table.”

He added that senators are also talking about alternative side-by-side proposals. “There’s not a resolution on this for us,” he said.

The emergency declaration fight presents a multi-pronged problem for Republicans, who need to agree on alternative language that both supports Trump on border security and expresses their constitutional concerns about his actions.

Asked about making changes to the House-passed resolution, a GOP aide said that the Senate “can amend whatever it wants,” but added that the parliamentarian has said there should be limits on amendments for the resolution to keep its privileged status.

But Republicans also expect Democrats to force a vote every six months on Trump’s emergency declaration, prolonging the political and legal headache.

Trump has sent multiple warning shots to Republicans, urging them to “stay united.”

He appeared confident on Friday that he would ultimately prevail, telling reporters at the White House that “we’re doing fine in Congress. They understand it’s an emergency.”

Sen. Susan Collins (Maine), one of the four Republican senators voting for the resolution, predicted that more of her colleagues would come out against Trump, though she declined to speculate on how many.

“I can tell you from talking with my colleagues that many are troubled, even those who are the strongest supporters of the president and his views on border security,” Collins said during an interview with CNN.

Though some GOP senators estimate that the number of Republican votes in favor of the resolution disapproving the emergency declaration could hit double digits, undecided senators have remained on the fence since Sen. Rand Paul (R-Ky.) offered his support more than a week ago.

Asked how he would vote, Sen. Mitt Romney (R-Utah) demurred, noting he didn’t yet know the text of the resolution that will be before the Senate.

“We have to see that before we can say for certain how we’re going to vote,” he said.

Sen. Lamar Alexander (R-Tenn.), who is retiring at the end of the current Congress, publicly urged Trump to withdraw the emergency declaration, but has not heard back from the White House about his idea.

One possible option under discussion would to get Trump roughly $5.7 billion for the wall, which Republicans support, but also block his emergency declaration. Republicans are also weighing changes to the National Emergency Act, including requiring that Congress affirmatively vote to continue the emergency declaration after a certain amount of time.

Sen. Rob Portman (R-Ohio) said during a conference call with Ohio reporters that he was trying to find an “alternative way” to get Trump funding, including expanding the amount of money he can take from the Pentagon’s counter-drug funds. Trump is expected to take roughly $2.5 billion from that pot though Republicans have floated expanding that to $4 billion.

Republicans argue that Trump could access nearly $6 billion in funding without needing to declare a national emergency-significantly more than lawmakers think he can use before the end of September, which marks the end of the fiscal year.

“There’s an overwhelming sense in the conference that the president needs to be able to build a barrier,” Lankford said. “It’s just a question of how those funds are used.”