During his primary, Donald Trump swore he could deport an estimated 11 million immigrants living in the country, illegally. In fact, with “really good management,” he vowed to get it done in two years. Then, he’d call on Mexico and get them to build a beautiful wall.

But now that Trump is the presumptive nominee, many Republicans in Congress are keeping their distance from what has become their nominee’s signature campaign issue and instead dismissed it as little more than stump speech bravado.

“Logistically that is an impossibility,” Rep. Renee Ellmers (R-NC), who has endorsed Trump and is facing a primary challenge from her right in June, told TPM. “It would cost the taxpayers of America. We would never get there… It would be an endless pursuit.”

Ellmers point was echoed by many experts and commentators when Trump first introduced his plan last summer. How would a Trump administration track down millions of people who were in the country illegally? Where would the estimated billions it would cost to deport them come from? And who would be tasked with carrying out such a massive deportation? Not to mention the moral and legal questions.

Ellmers said she believes Trump is just trying to send a broader message. He is telling Republican primary voters what they want to hear: it’s time to make a change in immigration policy.

A lot of Republicans on Capitol Hill in interviews Wednesday said that Trump’s plan is pretty far out there.

“That’s not realistic. I think that most people who look at that issue want a solution. They want tougher border enforcement, and they want to make sure that the people who are here illegally — particularly those who are committing crimes and have law enforcement issues — get sent back, but as we look at these issues, you have to consider what is actually doable,” said Sen. John Thune (R-SD)

Thune said that a lot of Republicans have raised the issue with Trump that deporting 11 million immigrants living in the shadows is probably out of the question. And many, including Senate Majority Whip John Cornyn (R-TX), have pointed out Trump could soften the tone he is sending to the Hispanic community.

Rep. Mick Mulvaney (R-S.C.), a member of the House Freedom Caucus, says he plans to bring it up with Trump when he sees him for a meeting in the upcoming weeks.

Mulvaney said he never “believed we were going to deport 11 million people.”

“Don’t know how you would even go about doing it,” Mulvaney said. “I look forward to having that debate with our presumptive nominee once he comes to meet with us.”

Trump’s policy is even more precarious for congressmen and senators facing re-elections in swing states and swing districts.

Rep. Carlos Curbelo (R-FL) says he won’t be supporting Trump at all in part because of his immigration policy.

“I called it a fraud from day one, from the day he announced it. It’s not a plan, alright, and it is unrealistic and it’s not a solution. It’s a good sound bite.”

Sens. Rob Portman (R-OH), Mark Kirk (R-IL), and Sen. John McCain (R-AZ) — all running for re-election — flatly said they didn’t support Trump’s deportation policy, although no one was anxious to spend time Wednesday talking about why.

When asked if he supported the plan, McCain–who has worked extensively on immigration reform on the Hill and supports a path to citizenship said– “of course not, but I’m in a Trump-free zone.”

Others teetering on the edge of re-election played coy. Sen. Pat Toomey (R-PA) paused for nearly 20 seconds before saying, “I have discussed my views on immigration pretty extensively and you can find that on my official website.”

Sen. Roy Blunt (R-MO) said he hadn’t seen Trump’s signature plan for deportation.

“I haven’t seen any plan to do that,” he said.

But one thing was clear, very few Republicans were ready to fully embrace their nominee’s plan to deport millions. (Rep. Mo Brooks (R-AL) was, but even he has not come out with a full endorsement for Trump.)

Most recognize that Trump could set the party back with the Latino community they have struggled to court. For more than a decade, Republicans have grappled with the policy and the politics of immigration, but most of the leaders working for reform imagined giving millions a path to citizenship, not deporting them.

In 2012, after Republican Mitt Romney won just 27 percent of the Latino vote, Republicans sought to find ways to do better with the Hispanic community.

Sen. Cory Gardner (R-CO) doesn’t support Trump’s plan. He said he’s confident that Trump’s idea is more talk than serious policy.

“He’s not gonna deport 11 million people,” Gardner said with a laugh.