Users from pro-Trump communities on 4chan and Reddit implored fellow members to vote for lower-polling candidates in online polls, specifically Tulsi Gabbard and Bill de Blasio, in the hours after Wednesday’s Democratic debate — a sign that digital manipulation efforts related to U.S. politics and elections remain very much alive.

Users on 4chan’s anonymous far-right /pol/message board repeatedly posted links to polls across the web, encouraging one another to “blow the polls out” for Gabbard, the congresswoman from Hawaii who has developed a substantial support base among many of its users.

The posts pointed users toward polls on national news websites like the Drudge Report, The Washington Examiner, and Heavy.com, but also polls from local news providers like NJ.com, which posts from several newspapers in the state.

“GIVE HER YOUR POWER,” read one 4chan post from 1 a.m. Thursday, pointing to a screenshot of the still-active Drudge poll showing Gabbard leading.

The efforts from 4chan’s /pol/ board and Reddit’s pro-Trump subreddit mirror the notorious troll communities’ strategy from 2016, when they bombarded polls in an effort to drive more visibility and confidence to their candidate of choice, and hoped news websites and candidates lent credibility to the results later on.

Traditional polls, such as those run by researchers, polling companies and universities are not susceptible to such manipulations. Pollsters usually call a diverse set of citizens from various levels of political engagement, and those polled are not allowed to vote several times or through automation, unlike many online polls.

The results from the poll on the Drudge Report, where Gabbard netted almost 40 percent of the vote, despite previously polling at less than 2 percent in national polls, created coverage in itself. The politics blog The Hill and The Daily Mail wrote about Gabbard’s performance in the poll, with The Daily Mail calling Gabbard the “shock winner” in the “first poll” after the debate. As more mainstream outlets pick up the methodologically questionable polls, the likelihood that they will be covered by more prominent news media and political figures increases.

With no publicly available data set, it’s not possible to know just how heavily potential manipulation factored into the results. The Drudge Report didn’t respond to NBC News emails requesting comment or clarification on its online voter fraud prevention measures.

Among disinformation experts, swarming a community or poll to bombard it with hypertargeted political messaging is called “brigading.” The practice is banned on sites like Reddit in order to prohibit fans of one politician or ideology from taking control of broader communities focused on politics and news and not one specific candidate.

Nina Jankowicz, author of the upcoming book “How to Lose the Information War” and a global fellow studying disinformation at the Wilson Center, a politics-focused think tank, called poll brigading a “basically less sophisticated form of astroturfing,” or simulating widespread support through artificial means.

She said news organizations need to be particularly careful not to credulously repeat unscientific poll results, as these sorts of targeted influence campaigns are now common.

“We should already be putting less stock in polls that are completely devoid of context, but especially examples like these which can be easily manipulated by bad actors,” Jankowicz said. “Given that we know this practice is going on, newspapers and other organizations running unscientific polls should introduce measures to make it more difficult to brigade results, such as sending unique links to individual emails.”

Poll brigading was an effective tactic for fans of then-candidate Donald Trump in 2016.

In the hours after general election debates, top posts on 4chan and Reddit’s largest pro-Trump community implored users to swarm online polls from national websites and local news affiliates asking who won the debate. Those poll results were touted by Trump on Twitter in the hours after the end of the debates.

Users on Reddit’s r/The_Donald, the site’s largest pro-Trump community, encouraged one another to vote for de Blasio, the mayor of New York, in Wednesday night’s Drudge Report poll and “LOL as these [expletive] run farther to the left.”

A 2014 Honolulu Civil Beat columnist noted Gabbard’s support over the years has included potentially inauthentic online users who aggressively attack critics and journalists. A recent NBC News analysis found Gabbard has received a disproportionate share of favorable coverage from Kremlin-linked media outlets.

While foreign influence has been a concern of politicians focused on election integrity, Jankowicz worried that this kind of targeted domestic trolling can pose an even larger disinformation threat.

“It’s absolutely important to report on the way domestic actors are influencing discourse,” Jankowicz said. “We are spending too much time worrying about foreign actors while acting completely ignorant of the threats in our own backyard.”