Immigration policy has long been a pivotal subject in Nevada, where one in every five residents hails from outside the U.S. This week, Sen. Dean Heller revealed flickers of concern about how decisive a role the issue could play in the Senate race.

At a closed-door meeting between President Donald Trump and Senate Republicans on Tuesday, Heller reportedly asked Trump to hold off on pushing for one of his major campaign promises until after the election: building a wall along the southern border. He was one of only two senators to get in a question.

Heller was concerned about the issue leading to a government shutdown, according to Politico. “As I told the President yesterday, we should not be debating a government shutdown in September,” Heller said in a statement to Politico on Wednesday. “Congress needs to do its job now and get the government funded before we break in August.”

Republicans in the meeting said Trump made it clear that he wanted to build the wall — a desire the president repeated on Wednesday, when he called for “full funding” of the wall at a meeting with California officials who opposed the state’s sanctuary city law, which limits local law enforcement cooperation with federal immigration authorities.

Heller posed his question after heaping praise on Trump and giving a pro-Trump account of his visit to Jerusalem for the opening of the U.S. embassy, the fulfillment of another Trump campaign promise to move the embassy from Tel Aviv in a controversial departure from decades of previous U.S. policy.

“He thanked him a lot,” Sen. Pat Roberts of Kansas said of Heller’s comments to Trump.

“Senator Heller just came back from Israel and he talked a little bit about how nice the ceremony was; how much he enjoyed it; and how popular Trump is in Israel right now, and he is very popular,” said Sen. John Kennedy of Louisiana.

Heller’s exchange with Trump mirrors the path he will likely have to walk to win re-election in a race where the margin of victory is expected to be close. He must keep Republican base voters and Trump supporters excited about his candidacy so they turn out to vote, while at the same time not repelling the moderate and independent voters who helped Hillary Clinton win the state in 2016.

It is a difficult assignment for Heller, who is the only Republican running in a state Hillary Clinton won. Trump typically uses his stance on immigration policy to rally his supporters, including in Michigan last month when he said “to protect our families, we must secure our borders.” He added that “our laws are so corrupt and stupid, I call them the dumbest immigration laws anywhere on earth.”

Heller’s office did not respond when asked for comment.

The exchange was one of a handful of flashpoints over immigration that has gripped the Capitol this week. It came as a growing group of House Republicans, including Nevada’s own Rep. Mark Amodei, has thrown their support behind legislation that would force votes on four separate immigration proposals if a majority of members sign on.

“I’m tired of defending no action,” said Amodei, who had signed on to a previous effort to force a vote on the bill that would legalize undocumented immigrants brought to the country as children, known as DREAMers, who meet certain requirements, and provide them a path to citizenship. The measure, known as the DREAM Act, is one of the four bills that would get a vote.

In February, a month before Danny Tarkanian dropped out of the Republican Senate primary, the Senate voted on three immigration proposals, none of which received enough votes to advance. Heller, who had been the target of attacks from Tarkanian that he did not support the president, voted for the proposal that was backed by Trump, which included a provision to limit legal immigration.

While Trump’s rhetoric and policies on immigration are a political benefit in some parts of the country, they are a liability for Heller in Nevada, where 20 percent of the state’s residents are immigrants themselves, according to the Census Bureau. Another 17 percent are native-born U.S. citizens with at least one immigrant parent, according to the American Immigration Council.

“I think it’s enormously complicated for him on immigration because the more he tries to moderate his position, the more he risks alienating the core, hard-right, very socially conservative base of Republican voters and I don’t know that the support he might pick up from maybe moderate or nonpartisan voters, including Latinos, would be enough to compensate for the votes that he’d lose,” said John Tuman, chair of the Department of Political Science at UNLV.

Just this week, there were reports that the Trump administration is proposing to separate children from parents who cross the border illegally. That comes after Trump’s decision to end the Deferred Action for Childhood Arrivals (DACA) program. DACA is the program that currently shields the DREAMers from deportation. Despite Trump’s move, his ability to end the program is being fought in court.

More than a third of the state’s immigrants are from Mexico, just over 14 percent are from the Philippines, more than 5 percent are from El Salvador and about 3 percent each are from China and Cuba, respectively, according to the American Immigration Council. The high concentration of Latino immigrants makes the issue especially relevant among voters.

“Many Latinos here, we know from field research, even if they don’t have a family member who has been caught up in removal proceedings or is at risk of it...they know people in their community who are and that gives them a personal connection to the issue,” Tuman said.

Adding to the headwinds facing Heller, Trump and Congress are on a collision course over funding for the southern border wall, which could result in another government shutdown, which could hurt vulnerable Republicans like Heller. The government shut down for three days in January over the immigration issue.

In the most recent spending package, Trump got $1.6 billion for the wall. Full funding would require about $25 billion.

If Trump wants more wall funding “then he has to find the votes without Democrats,” said Arizona Democratic Rep. Ruben Gallego, who is a leader of the Congressional Hispanic Caucus.

Gallego and others in the House who want action on an immigration bill are backing an effort led by Rep. Jeff Denham, a Republican from California. Denham has filed what is known as a discharge petition, which is a House process that allows a bill to come to the floor if a majority of members sign the petition.

Twenty-five Republicans need to sign the petition if all Democrats sign the measure. Democrats had held back their signatures in order to entice the requisite number of Republicans to sign on. The measure would trigger votes on four proposals, including the DREAM Act, a bill sponsored by Denham that would combine a pathway to citizenship for DREAMers with $550 million over five years in border security funding, and a measure of House Speaker Paul Ryan’s choosing. 

So far, 20 Republicans have signed on, including Amodei, who is considering supporting a conservative measure sponsored by Republican Rep. Bob Goodlatte of Virginia, that would address the status of DREAMers and include authorization for funding for Trump’s wall along the southern border.

“I would like to see one house of the federal legislature act like a legislature and bring something to the floor, allow it to be amended, or not, see where the votes are and then vote it up or down,” Amodei said. “So we’ll see what that produces. And if it produces nothing, then at least you’ve got a voting record because right now anybody can say anything about any of us with respect to [immigration] because there is nothing of substance in terms of how did you vote.”

House Republican leaders have urged their colleagues to not sign the petition, and Ryan is working with Denham and the White House to come up with an alternative that can win a majority in the House, Denham said Friday. However, Denham is still pursuing his petition, which he contends has brought the issue to a head. “Until we have a bill that has a consensus, we’re going to continue to move forward,” Denham said.

But some in the House Freedom Caucus, a group of ultra-conservative House Republicans, are also skeptical of the petition because it would yield a more moderate measure.

“I don’t think it will ever come to fruition because there are too many procedural ways that you can stop it from happening,” said North Carolina Republican Rep. Mark Meadows, who is chairman of the Freedom Caucus.

Concern over the possible success of the immigration effort led some conservatives to vote against a bill to reauthorize the nation’s agriculture and anti-hunger programs, also known as the farm bill. The bill failed to pass the House Friday throwing into question the future of one of the year’s must-pass pieces of legislation. Authorization of agriculture and related programs expires at the end of the fiscal year, Sept. 30.

Rep. Scott Perry, a Republican from Pennsylvania and a member of the Freedom Caucus, acknowledged that taking down farm bill was part of the group’s leverage on immigration. He also argued that discharge petition would undermine the results of the 2016 election, when Republicans campaigned on a hardline stance on the issue and won the White House as well as the majority in both chambers of congress.

“That...disavows what the last election was about and what the majority of the American people want and the people in this body know it,” Perry said.