United States: Who is Stephen “Voldemort” Miller, Donald Trump’s new chief of staff?

California gave him a little nickname: “Voldemort”. This shows that Stephen Miller, appointed Donald Trump's chief of staff on Friday, comes forward with a sympathetic air. As a result of the Republicans' rout in Tuesday's midterms, this member of the most radical wing of the American conservative movement replaces Susie Wiles.

Stephen Miller is the faithful among the faithful. “No one is more loyal, hard-working, or more connected to the America First movement than Stephen,” says Karoline Leavitt, White House spokesperson until August 2026. At 41, this spearhead of the radical right has one obsession: “saving” the West in the face of the “invasion” of migrants. For him, “it’s a fight to save civilization.”

He’s “Trump’s brain”

Until now, Miller served as deputy chief of staff for political strategy and homeland security adviser. And behind all the decisions bordering on legality to act against migrants, its shadow looms. According to the Wall Street Journal, it was he who, in May 2025, ordered ICE, the immigration police, to redouble their efforts to increase the number of deportations. In January, he described Alex Pretti, the second American killed in Minneapolis in the space of a few weeks by federal agents, as a “terrorist”. He then returned to his statements.

Not sure if it's a compliment, but Kevin McCarthy, former Speaker of the House of Representatives, told the New York Times in January 2025, just before the Republican president's inauguration, that "Stephen Miller is the 'brain of Trump'." His influence would be sprawling, details the book Regime Change, which describes a man quick to attack his teams harshly.

Married to a “tradwife”

Born in California into a Jewish family, to parents who attended prestigious universities, Stephen Miller had the profile of a future democrat. But from high school, then at Duke University, he provocatively defended the ideas of the radical right. David Horowitz, an influential conservative ideologue, offered him his ticket into ultraconservative circles, where he met figures like Steve Bannon and Tucker Carlson before joining, at the age of 30, Donald Trump's first campaign.

His wife, Katie Miller, is also an influential figure in the radical right sphere. She was for a time the spokesperson for Elon Musk's Doge Commission, and echoed Donald Trump's territorial claims on Greenland. Katie Miller has since become a Maga influencer, also part of the “tradwife” movement, which advocates male domination in the couple.

The architect of the “Muslim ban”

During Donald Trump's first term, between 2017 and 2021, Stephen Miller's xenophobic ideas were already there, but less established than today. He was an architect of the “Muslim ban”, these restrictions on entry into the country imposed on nationals of predominantly Muslim countries, which then came up against the courts.

The advisor also supported his boss when after the assault on the Capitol on January 6, 2021, to prevent the certification of Joe Biden's victory.