U.S. Ambassador to the United Nations Nikki Haley. (Jahi Chikwendiu/The Washington Post)

It's a common disclaimer in Twitter users' bios: “Retweets ≠ endorsements.” Maybe Nikki Haley should have included it in hers. Maybe it wouldn't have mattered.

The U.S. ambassador to the United Nations has received a warning from the U.S. Office of Special Counsel, which polices the Hatch Act's restrictions on political activity by federal employees.

Haley's violation? Retweeting a Twitter message posted by President Trump in which Trump endorsed the congressional candidacy of South Carolina Republican Ralph Norman. OSC ruled that Haley, the former governor of South Carolina, had effectively given her endorsement to Norman, too.

In other words, retweets do equal endorsements — at least when it comes to enforcing the Hatch Act, which prohibits most government workers from using their “official authority or influence for the purpose of interfering with or affecting the result of an election.” The president and vice president are exempt, which is why Trump's original tweet was permissible.

Here's an excerpt of OSC's rationale, authored by Erica S. Hamrick, deputy chief of the Hatch Act unit:

At the time of the retweet at issue, her Twitter profile picture was an official government headshot with the American flag displayed behind her, and her Twitter header picture was a photograph of Ambassador Haley with President Trump and other members of the United Nations Security Council in a room at the White House. Her profile information listed her as “United States ambassador to the United Nations,” and many of her posts and photographs were about and of official matters . . .

Here, because Ambassador Haley's personal Twitter account included so much indicia of her official role as ambassador and was even linked to the United States Mission to the United Nations website, it gave the impression that she was acting in her official capacity when she used this account to retweet President Trump's message.

Notice that when judging whether Haley's retweet constituted a Hatch Act violation, OSC carefully considered whether she appeared to be acting in her official capacity. But Hamrick's explanation indicates no debate about whether a retweet constituted an endorsement. Regulators clearly believed it did; the only question was whether Haley seemed to be throwing her “official authority or influence” into the endorsement.

The warning to Haley does not mean that all retweets are endorsements, of course. Some Twitter users, including many journalists, routinely retweet messages that are simply notable or newsworthy. Because they do this on a regular basis, their followers understand that retweets do not imply agreement.

But OSC's ruling in the Haley case is a reminder to politicians that the default assumption, when they retweet a message, is that they share the expressed sentiment.