In the closing weeks of his 2024 campaign, Trump aired false claims about weather manipulation and government assistance after hurricanes hit North Carolina, a swing state he would ultimately win.

With fewer checks from social media platforms and the struggling traditional media, he also complained -- without evidence -- about voter fraud, the 2020 election, the Covid-19 pandemic, vaccine harms and more.

These claims ricocheted across the internet through a network of social media influencers, who in many cases have become news sources for the public as media become increasingly fragmented.

"The problem of misinformation and disinformation is the worst it's ever been," said Bill Adair, a Duke University professor who founded the fact-checking site PolitiFact and authored the 2024 book "Beyond the Big Lie."

The tactics designed to contain and correct misinformation, such as fact-checking and social media moderation, "are clearly not working," Adair added.

He predicted few changes ahead from platforms that have largely exempted elected officials from fact-checking "because they don't want to make the politicians mad."

Even as the 2024 campaign was under way, polls found roughly one-third of Americans believed the 2020 election was stolen by Joe Biden.

Misinformation researchers at NewsGuard found 963 websites and 793 social media accounts that have repeatedly published false election information, and 1,283 partisan websites masquerading as neutral news organizations during the campaign.

"The right has invested, since 2016, in building participatory, activist, factional social media networks that are directly tied into its 'small batch' propaganda media ecosystem," said Renee DiResta, a misinformation researcher, in a Threads post.

"Things move from one sphere to the next: rumors are picked up by the propaganda machine if useful. Memes shape the messaging.

"The influencers boost each other."

Ethan Porter, a researcher and professor at George Washington University, said that while misinformation efforts may not have been decisive in his victory, "Trump was almost certainly helped by Twitter/X's apparent refusal to contain or mitigate pro-Trump misinformation."

- Science and health -

The upcoming four more years for Trump have raised concerns of legitimizing misinformation about vaccines, climate change and other health issues given his alliance with Robert F. Kennedy Jr., whose nonprofit has been a major promoter of false conspiracy theories on Covid-19.

"How are people not alarmed by Trump wanting RFK Jr, a person who has no formal education in health care, in charge of health... this man has promoted anti-vaccine misinformation and public-health conspiracy theories for years," Alma Hernandez, a Democratic member of the Arizona House of Representatives, said on X.

The Union of Concerned Scientists said the first Trump administration made 1,400 changes to agency websites that removed science-based information on environmental issues such as water pollution, climate change, and endangered species.

"President-elect Trump's path to the White House has been an unprecedented campaign of disinformation, threats, divisive language, and dangerous policy promises. It's understandable to look ahead to the next four years with serious worry," acting president Kim Waddell said in a statement.

- Muzzling the media -

Trump's attacks on the media have also raised alarm bells about coverage of his administration.

Journalist and author Kyle Paoletta wrote that he fears "Trump's assault on the press will become a fusillade of discreet attempts to quash whatever reporting he views as antagonistic" and questions whether reporters will maintain access or face harassment.

In a similar way, social media has retreated in content moderation as misinformation researchers face threats and attacks from conservative lawmakers.

Since taking over Twitter, now known as X, Elon Musk -- who may join Trump's cabinet -- has amplified rather than curbed misinformation.

Matt Gertz of the left-leaning watchdog Media Matters said Trump won over voters thanks in part to "a right-wing media complex that bombards them with falsehoods and grievances while dissuading them from consulting any alternative sources of information, be they legacy news outlets or government officials or medical experts."

Daniel Kreiss, a professor and researcher at the University of North Carolina Center for Information, Technology and Public Life, said the failure of fact-checking and traditional reporting to stem the spread of misinformation could be "devastating."

"What we're going to see are concerted campaigns to undermine democratic institutions and democratic norms," Kreiss said.