In an interview, Taylor said his understanding was that Trump wanted to make the announcement during the State of the Union speech.

“That’s what White House staff warned us, which is why we rushed to the White House,” said Taylor, who is best known for writing an anonymous op-ed in The New York Times in 2018 describing a “quiet resistance” in the Trump administration.

In order to use the military on American soil, Trump wanted to invoke the Insurrection Act, which allows the president to deploy the armed forces in a law enforcement role, Taylor writes in the book — something troops are normally prohibited from doing. Trump and other presidents, including Barack Obama and Joe Biden, have sent the military to the border, but they were mostly relegated to supporting federal agents handling the influx.

The issue of using troops for law enforcement made headlines in the summer of 2020, when Trump threatened to invoke the act to send the military to quell protests against racial injustice and police violence in American cities. But in February 2019, when Trump considered using troops against migrants, such a move was almost unheard of. Taylor writes that deploying the act “is the closest thing to ‘martial law’ in our system.”

“Until the Trump administration, the proposition had sounded like the plot of a bad fiction novel,” Taylor writes. “But Donald Trump was a few sentences away from making it happen. I was there.”

Taylor got the call about Trump’s plan on Feb. 4, 2019, he writes, one day before the speech. He and his boss Kirstjen Nielsen, then the secretary of Homeland Security, rushed to the White House to stop him.

“This is fucking insane,” Trump told them of the migrants during a conversation in the White House’s Map Room. “We can’t let them in.”

The president gave Nielsen and Taylor permission to close U.S. ports and “send them back.” Then, “he told us to use the military, which I interpreted as a nod to the Insurrection Act that aides had warned me about,” Taylor writes.

That day, Nielsen and Taylor spent “hours” trying to convince the White House staff and the counsel’s office to weigh in.

“If he invoked the Insurrection Act, it would set a dangerous precedent,” Taylor writes. “There was no telling where Trump might use it next.”

Taylor and Nielsen eventually went back to the president with an alternative: they were working with Mexican authorities to contain the situation, so there was no need for “extraordinary measures.” Their work “bought just enough time to throw him off the idea,” Taylor writes.

The State of the Union “was finalized without any reference to the Insurrection Act,” he says in the book.

Steven Cheung, a spokesperson for Trump, said Taylor is “a sack of shit. His book either belongs in the discount bin of the fiction section or should be repurposed as toilet paper.”

Nielsen did not respond to a request for comment. Another former senior DHS official, who was granted anonymity to speak about a sensitive discussion, said they did not recollect any planning for invoking the Insurrection Act at the time. The person said Trump often threw out suggestions in order to get his staff to explain their views, but the idea that the president was close to invoking that Act is “fantastical.”

During the later uproar over using the Insurrection Act against protesters in 2020, Jim Mattis, who resigned as Trump’s defense secretary in 2018, made rare public comments condemning the idea, which was never carried out.

“I swore an oath to support and defend the Constitution. Never did I dream that troops taking that same oath would be ordered under any circumstance to violate the Constitutional rights of their fellow citizens,” Mattis wrote in The Atlantic. “We must reflect any thinking of our cities as a ‘battle space.’”