Now, Trump is getting the hearty backing -- or at least strong cooperation -- of rank and file Republicans and GOP leaders to build the border wall many of those same officials once called an overly costly and insufficiently effective border security measure.
House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell said Thursday at the Congressional GOP retreat in Philadelphia that they would push ahead with legislation to fund Trump's wall, which they estimated would carry a $12 billion to $15 billion price tag.
Just weeks earlier, McConnell was dodging reporters' questions about whether he'd support a wall. And during the presidential campaign, both McConnell and Ryan argued that there were smarter ways to secure the border.
The switch marks the reversal of several years during which Republicans have distanced themselves from proposals calling for a physical barrier at the border in favor of more advanced technology and a broader focus on comprehensive immigration reform. And it raises the specter that Republicans could soon get on board with many of Trump's hardline policies on immigration -- like mass deportations -- and other issues, like trade.
Asked what changed to get Republicans on board with paying for a wall, Rep. Mark Meadows, R-North Carolina, put it bluntly: "November 8."
"Let's be frank: politics have consequences. November 8 happened, that's why a wall is going to be built," said Meadows, who chairs the small but influential House Freedom Caucus, home to some of Capitol Hill's most conservative Republicans.
House Majority Leader Eric Cantor's stunning primary defeat two years ago on the issue of immigration started Republicans down the path, Meadows said, and Trump's victory last year completed it.
"You know, the whole immigration issue changed dramatically in the House when Eric Cantor lost," he said. "Those two things were political in nature, but they had real legislative consequences. So I think November 8 happened and that's what finished the evolution."
But while that evolution was taking place among grassroots conservatives, another one was taking shape among Republican leaders in Washington. GOP presidential nominee Mitt Romney's defeat in the 2012 election resulted in a post-mortem that concluded Republicans needed to move away from hardline immigration policies that alienated Hispanic voters in favor of a more moderate stance -- one focused on securing the border with more resources and modern technologies (not a wall) and increasingly support for pathways to legalization for at least a portion of the roughly 11 million undocumented immigrants in the US.
It's the collision of those two movements -- one leading Republicans further down a path of hardline immigration policies and the other toward a more moderate, bipartisan approach -- that helped catapult Trump to the top of the GOP primary horserace.
While Trump surged in the polls by decrying failed immigration policies, overstating the numbers of crimes committed by undocumented immigrants and vowing to build a wall, his opponents waffled.
New Jersey Gov. Chris Christie, who would eventually become the first of Trump's primary opponents to endorse him, for months mocked Trump's proposal to build a wall. Former Florida Gov. Jeb Bush said a wall wouldn't work and wasn't a "practical" solution.
Pressed during a March 2016 interview, Ryan signaled, with a grin, that he wouldn't fund Trump's border wall: "Uh, remember we're not going to pay for that, recall?"
"We think we should secure the border that's for sure," Ryan said, but he pointed to congressional task forces that have identified non-wall based solutions to securing the border.
Now, the man Trump once called "very, very weak on illegal immigration" is priming the pump to pay for Trump's wall proposal -- despite a total lack of certainty about Trump's pledge to compel Mexico to foot the bill for the multibillion-dollar proposal that appears at odds with Republicans' fiscal conservatism.
Ryan dodged Friday when asked about the prospects of Mexico paying for the wall
"I'm not going to get into a quibbling about whether they should or should not pay for it, because we need to get something done," Ryan said at a Politico event Friday.
But how much further will Ryan and other GOP leaders go?
Trump has also called for mass deportations of undocumented immigrants and appeared to lay the groundwork for such steps in the executive orders he signed Wednesday, which included boosting Border Patrol forces by 5,000 and hiring 10,000 more immigration enforcement officers responsible for carrying out deportations.
Rep. Ryan Costello, a Pennsylvania Republican, said he thought many Republicans did not take Trump literally last year when he talked of building a wall.
"I've viewed that statement, 'Building the wall,' metaphorically, right? And I think a lot of Republicans did," Costello said.
He said many Republicans understood it as more about securing the Mexican border and took Trump's campaign jargon to mean other options, like improved surveillance.
"From my perspective and from I think most people's perspectives, you want to do what works and leave the -- whether this particular portion of the secured borders is an actual, physical erection of a wall or isn't I think that that's sort of subordinate to the principle goal of securing the southern border," Costello said.