New York Times best-selling author and populist conservative columnist Ann Coulter says former voters of President Trump “should put the fear of God in him,” as the border wall — the central promise of his “America First” agenda — remains unbuilt.

In an interview with the New York Times‘ Frank Bruni, Coulter said it is Trump’s core base of working and middle-class supporters whom the president should be the most fearful of, mainly because he has yet to fulfill his promise of building a wall along the U.S.-Mexico border and reducing legal immigration to the U.S. to raise Americans’ wages.

Frank Bruni: The $1.3 trillion spending bill that he signed last week sent you over the edge. Ann Coulter: Yes. This is a different category you’re seeing now: Former Trumpers. That should be terrifying to the president. Maybe he’ll actually keep his promises. Unlike Marco Rubio. Unlike the rest of them. Unlike Mitch McConnell. We have been betrayed over and over and over with presidents promising to do something about immigration. If he played us for suckers, oh, you will not see rage like you have seen. Immigration should be a bipartisan issue. I wish Trump would give something like a fireside chat. That’s what he should have done the day of his inauguration: Sit in the Oval Office and say, perfectly somberly and kindly: “I said some wild things during the campaign, it sounds like it’s divisive and angry, but now we need to bring the country together. We can disagree on other things, but one thing that ought to unite us is that we want to protect the people already here.” It’s a perfectly bipartisan issue.

Coulter also said that reducing legal immigration and building a border wall to stop illegal immigration is the most important issue to Trump’s base of support, or as she calls them in the interview, “Former Trumpers.”

“If he doesn’t have [Former Trumpers] anymore — that’s what he should be worried about, because, you play those people for suckers? The ones who stood by him through thick and thin and thought this was finally something different? Former Trumpers should put the fear of God in him,” Coulter said.

Weeks ago, Trump set off a firestorm among his base of supporters when he signed off on House Speaker Paul Ryan’s omnibus spending bill that does not include a single provision from the president’s 70-point list of pro-American immigration reforms.

Those reforms include building a wall along the southern border, ending chain migration (which would cut legal immigration in half), mandating E-Verify to ban employers from hiring illegal aliens, and ending the “Catch and Release” program that releases illegal aliens into the interior of the country.

At the time, Coulter blasted Trump, saying “in one generation,” the U.S. would become South Africa.

Ann Coulter: ‘In One Generation’ U.S. Will Be ‘South Africa,’ Trump ‘Betrayed’ Voters with ‘Paul Ryan Republicanism’https://t.co/cr6Ehc46SN — John Binder 👽 (@JxhnBinder) March 24, 2018

The omnibus bans Trump from building a border wall with the proven-effective prototype walls that he visited earlier this month in San Diego, California. Additionally, it increases the Catch and Release program and does not increase the number of federal deportation agents to more swiftly deport illegal aliens living in the U.S.

After upsetting his conservative and economic nationalist base of support, he took to Twitter to claim that a Calexico, California construction project along the U.S.-Mexico border was part of his border wall being constructed, as Breitbart News reported.

Great briefing this afternoon on the start of our Southern Border WALL! pic.twitter.com/pmCNoxxlkH — Donald J. Trump (@realDonaldTrump) March 28, 2018

The project in Calexico, depicted in the photos shared by the president, was funded in Fiscal Year 2017 and does not include any of the prototype border walls that Trump toured.

Instead, the project consists of 30-foot high bollard style fencing on a 2.2.5-mile section that spans from Calexico’s West Port of Entry to beyond the Gran Plaza Outlets. The project, as mentioned by the Department of Homeland Security (DHS), also includes 2.25 miles worth of new roads along the southern border.

Every year, the U.S. admits more than 1.5 million legal and illegal immigrants, with the vast majority arriving in the country as foreign relatives to naturalized citizens. In 2016, the legal and illegal immigrant population reached a record high of 44 million. By 2023, the Center for Immigration Studies estimates that the legal and illegal immigrant population of the U.S. will make up nearly 15 percent of the entire U.S. population.