Mark Roberts, a congressional candidate in Oregon, suggested Monday that First Lady Melania Trump is a sex worker — and as the post has gone mega-viral on Twitter, the Silicon Valley company’s inaction provides a clear view of how its “hate speech” rules are selectively enforced only against conservatives and populists.

Roberts, running as an independent against Rep. Greg Walden (R-OR), attacked the First Lady in response to a tweet by Turning Point founder Charlie Kirk contrasting the size of Mrs. Trump’s and Michelle Obama’s personal staffs.

“There are thirty-nine fewer staffers dedicated to The First Lady of the United States (FLOTUS) than under Obama,” tweeted Kirk. “There are only five staffers dedicated to Melania Trump vs. forty-four staffers who served Michelle Obama.”

In response, Roberts — a Verified account — tweeted: “Did you know the First Lady works by the hour? #thinkdirty #hoebag.”

After 21 hours and much reporting from prominent conservatives, Twitter has apparently not suspended Roberts or demanded the deletion of his post.

UPDATE: A post from Roberts purportedly shows that Twitter has reviewed reports on the Melania tweet and declared it does not violate its terms of service.

Roberts, for his part, has doubled down on the salacious claim, apparently defending his post from a critic by suggesting Mrs. Trump acts like a “professional hooker.” “Did you see the naked pix to prove it?” he quipped to another user.

By contrast, in just the past week, Twitter has aggressively censored other conservatives for mainstream views expressed on the platform. The Federalist’s Kathleen McKinley was reportedly barred last Friday after expressing opposition to honor killings and transgender soldiers serving in the U.S. military. To restore her account, Twitter forced McKinley to deleted the two tweets, one a year old and the other posted one month ago, because they were found to have purportedly violated the tech giant’s “rules against hateful conduct.”

In addition to censoring McKinley, Twitter suspended GOP Missouri Senate candidate Austin Petersen following a mass-reporting campaign by far-left Shareblue activists.

As previously reported by Allum Bokhari, “The incident began when Shareblue activist Caroline Orr made a tweet attempting to draw a link between Petersen’s candidacy and the alleged Russian hack on Senator Claire McCaskill, the Democratic Senate incumbent in Missouri. Petersen then responded with an animated picture (better known as a gif) of Joseph Stalin waving with the caption “off to Gulag now.” It’s a gif that Petersen took from Twitter’s own library of shareable gifs.”

Representatives for Twitter did not immediately respond to a request for comment.