The story quickly mushroomed online and in social media, with stunned reaction at the idea of the U.S. government deploying a hundred thousand armed troops around the country, away from the border. Reporters scrambled to figure out what the legal authority for the move would be, and to figure out how state governments might react.

And yet some people immediately sensed that something about the story seemed off:

How long before this turns out to be highly exaggerated/not true at all? https://t.co/inuI9vIhYL — neontaster (@neontaster) February 17, 2017

Within minutes, in fact, Trump officials denied the story, on the record, to reporters. Press Secretary Sean Spicer spoke to a White House reporters as President Trump prepared to leave for a trip to South Carolina, saying, “That is 100% not true. It is false. It is irresponsible to be saying this. There is no effort at all to round up, to utilize the National Guard to round up illegal immigrants.”

But Spicer’s comment added two interesting wrinkles. First, he scolded the AP for not seeking comment before publishing the story. But as a reporter responded, the AP had asked both the White House and the Department of Homeland Security for comment multiple times before publication, and had received nothing.

Spicer also said, “It is not a White House document.” That statement was intriguing, because Spicer wasn’t denying that the memo was real; he was only saying it came from outside the White House. But that didn’t conflict with the AP report, which said the memo was written by Secretary of Homeland Security John Kelly. “I don’t know what could potentially be out there, but I know that there is no effort to do what is potentially suggested,” Spicer added.

Meanwhile, other reporters were trying to get DHS to explain what was going on.

DHS confirms that the memo reported by AP did exist; but they said it was "never seriously considered" https://t.co/4kB6rLfyCX — Jamie Dupree (@jamiedupree) February 17, 2017

In other words, the memo was in fact real. The full text was available online within about 90 minutes of the original AP tweet. It is hardly a skimpy document—it’s full of bullet points, legal citations, and footnotes. And it also offered some clarity. The clause the AP report referenced involved inviting states to enroll guardsmen in the existing federal 287(g) program that authorizes state law-enforcement officials “to perform the functions of an immigration officer” with respect to “the investigation, apprehension, and detention of aliens.” Notably, that would require the governors of individual states to decide whether or how to participate, and it is framed as an expansion of current efforts rather than a dramatic shift in policy.

Still unresolved is the question of how serious a proposal the memorandum may be, or whether it remains under active consideration. There are a range of possibilities: It had been considered but rejected as outlandish. It’s part of a plan that’s still in drafting. Maybe someone asked Kelly what it would take to expel a huge number of immigrants, and this was his back-of-the-envelope calculation. This is a question that DHS could have resolved by commenting to the AP before publication.