A nine-letter social media post was all it took for the Department of Homeland Security to spark a torrent of backlash online this week, drawing the ire of politicians and prompting comparisons to Europe’s far right.

On Tuesday afternoon, DHS posted a declaration on X for immigrants to “remigrate,” threading a link to the agency’s self-deportation app.

At first glance, the post could be seen as a straightforward reference to the Trump administration’s long-standing immigration policies, which have called for immigrants to “voluntarily self-deport” back to their home countries.

But experts who study and monitor extremism and the far right told CNN they’d urge caution when invoking the word, which has historic roots, including Nazi ideology and, more recently, a violent conspiracy theory that’s inspired terrorist attacks in the US and abroad.

Here’s what we know:

A brief, dark history of a loaded word

Extremism expert Cynthia Miller-Idriss was researching Nazi iconography for her 2019 book when she said she came across an image that made her pause.

The picture – emblazoned on a T-shirt – showed Jewish people being loaded onto a ship bound for Madagascar. It was captioned, “Have a nice trip,” she said.

And it was a reference to the Nazis’ “Madagascar Plan.”

In the late 1930s, “before the concentration camps and gas chambers … there was a solution to remigrate Jews to Madagascar,” Miller-Idriss explained.

Indeed, Adolf Hitler weighed multiple remigration policies and other antisemitic proposals before arriving at his final, d