In the hours after a chaotic confrontation in Chicago last week that culminated with a federal agent shooting a local woman, top White House aide Stephen Miller delivered an urgent order to Department of Defense personnel: Prepare to send in the troops.

The facts on the ground at the time remained murky. Federal officials claimed local police were refusing to provide backup as they struggled to maintain control of the scene. The Chicago Police Department said otherwise, insisting officers were immediately sent to help out.

But inside a West Wing that had waffled for weeks over the momentous step of dispatching National Guard to the nation’s third-largest city, it offered a clear impetus, two sources familiar with the discussions said.

“Domestic terrorism and seditious insurrection,” Miller labeled the scene in a social media post, as administration officials hurried to draw up a deployment plan in a matter of hours.

The abrupt decision to send the National Guard into Chicago has ratcheted tensions between the White House and Democratic-led Illinois to new heights in the days since. It’s opened a volatile new front in President Donald Trump’s offensive in blue cities, while further testing the limits of his rapidly expanding authority.

And at the center of the controversial operation is Miller — the White House deputy chief of staff for policy who has accumulated such sprawling influence over the administration’s activities that he’s often referred to in Trump circles simply as “the prime minister.”

Miller attends a meeting with US President Donald Trump and Philippine President Ferdinand Marcos Jr., in the Oval Office on July 22. Chip Somodevilla/Getty Images

Miller’s existential showdown

The 40-year-old immigration hardliner has spearheaded the federal government’s increasing encroachment into Democratic cities, marshaling federal law enforcement forces behind the scenes to carry out deportation raids and coordinate crackdowns that