Republican Senator Lindsey Graham on Friday morning blamed the looming government shutdown on right-wing White House adviser Stephen Miller, accusing him of poisoning the President Donald Trump’s mind on the bipartisan immigration deal that Graham was championing. “The Stephen Miller approach to immigration has no viability,” Graham told MSNBC. “Tuesday, the president was in a good place. He was the president of all of us. He spoke compassionately about immigration, tough on security, he wanted bipartisanship. Two days later, there was a major change. I think the change comes about from people like Mr. Miller. Mr. Miller is well known in the Senate for having views that are outside the mainstream.”

Graham’s analysis is spot on, but Miller is not a rogue actor; he’s representative of the hardcore anti-immigration forces in the Republican Party, who want to clamp down not just on undocumented immigrants but also curtail legal immigration. The shutdown drama—Congress must act to fund the government by midnight on Friday—is driven by the fact that Trump is struggling to satisfy two major wings of his party: mainstream Republicans like Graham, who are eager to pass a bill protecting immigrants brought to the United States as children (known as Dreamers), and restrictionists like Miller, who want to use the leverage of current negotiations to pursue a wider anti-immigration agenda that includes funding for the border wall and ends the family visa and diversity visa programs.

Hard-core immigration restrictionists are a minority of the American population, and possibly even of the GOP. Polls show that support for immigration, including providing a pathway to citizenship for Dreamers, is broadly popular with most Americans. But restrictionism is popular with Trump’s base and the White House itself. As Axios reports, after the infamous meeting last week where Trump decried immigration from “shithole countries” and rejected the bipartisan compromise put forward by senators Dick Durbin, Jeff Flake, and Graham, members of the White House circulated a memo titled “Flake-Graham-Durbin Proposal Would Cripple Border Security and Expand Chain Migration.” This memo, Axios notes, “shows how far the White House is from ever agreeing to the Graham-Durbin legislation. Several moderate Senate Republicans and Democrats have embraced this legislation. But GOP leadership considered it dead on arrival, and immigration hawks like Tom Cotton and Stephen Miller hate it.”

The strength of the immigration hawks comes not just from figures like Senator Cotton and Miller, but from their megaphone: the right-wing media. Trump’s presidency has created a feedback loop in which the president’s xenophobia and racism—from his claim that Mexican immigrants are rapists to his recent “shithole” remark—have emboldened prominent white nationalists to express their views forthrightly on Fox News. This, in turn, emboldens Trump himself, since he watches Fox News for cues on how to please his right-wing base, thereby making it harder for Trump to compromise on issues like protecting Dreamers.

This feedback loop can be seen regularly on Tucker Carlson’s prime-time show, which has become a major forum for mainstreaming racism. On Thursday night, Carlson interviewed Canadian pundit Mark Steyn, who took issue with CNN host Chris Cuomo for warning about the dangers of white supremacists.