When President Trump visited China in late 2017, Xi Jinping welcomed him with a grand display of Chinese history and culture: a four-hour private tour of the Forbidden City culminating in a performance by the Peking Opera.

Eight years, a pandemic and two trade wars later, Mr. Trump is returning to Beijing, where the theme of future dominance, not ancient majesty, has filled domestic and international headlines with articles about dancing robots, drone swarms and the quiet hum of electric vehicles.

China increasingly casts itself not as a fading civilization trying to catch up to the West but as a superpower poised to surpass it. Chinese nationalists and state-linked commentators say they have Mr. Trump to thank. America under his rule, they say, validates Mr. Xi’s worldview centered on “the rise of the East and decline of the West.”

For decades, many Chinese viewed the United States with a mix of admiration, envy and resentment. America represented wealth, technological sophistication and institutional confidence. Even critics of Washington who reviled the American system often assumed that it worked.

Mr. Trump’s ascent and his volatile second term shattered that image.

In January, a nationalistic Beijing think tank affiliated with Renmin University published a triumphant report about Mr. Trump’s first year back in office. The report argued that his tariffs, attacks on allies, anti-immigration policies and assaults on the American political establishment had inadvertently strengthened China while weakening the United States. Its title: “Thank Trump.”

The report called Mr. Trump an “accelerator of American political decay,” with the United States sliding toward polarization, institutional dysfunction and even “Latin American-style instability.” His hostility toward China, the authors argued, was a “reverse booster” that unified the country and helped bring about its strategic self-reliance.

“At this turning point in history,” the authors wrote, “what we hear is the heavy and haunting toll of an empire’s evening bell.”

Such language, once confined largely to nationalist corners of the Chinese internet, has increasingly entered mainstream political discourse.

Evidence of this shift is measurable: The use of terms related to “American decline” in official Chinese sources nearly doubled in 2025, according to a study by two Brookings Institution researchers.

The narrative of American decline did not begin with Mr. Trump. For years, Chinese state media and nationalist pundits have highlighted mass shootings, homelessness, political polarization and economic inequality in the United States as evidence of the failures of Western democracy. More recently, official outlets embraced the viral phrase “kill line,” borrowed from video game culture, to describe what they portrayed as the irreversible downward spiral facing America’s working poor. It’s a familiar tactic of the Communist Party to distract the Chinese public from the country’s own issues.

But Mr. Trump’s return to office and his administration’s erratic decision-making in both domestic and foreign policy have supplied the propaganda machine with plentiful fresh material. Images of immigration raids, the Minneapolis shootings and bitter political infighting circulate widely on Chinese social media alongside triumphant commentary about American dysfunction. What once sounded to many educated Chinese like exaggerated propaganda increasingly feels, to some, observational.

A 31-year-old education consultant in northern China who advises families on overseas study told me that parents who had once aspired to Ivy League degrees for their children now saw America as “too chaotic.” A decade ago, more than 80 percent of his students considered the United States for study abroad, said the consultant, who asked me to use only his family name, Wang, for fear of government retribution. Now, he estimated, the figure has fallen to 45 percent.

Mr. Wang described watching footage of the Jan. 6, 2021, attack on the U.S. Capitol and finding himself thinking of the Red Guards that Mao Zedong dispatched to tear apart China’s institutions during the Cultural Revolution. That feeling returned more insistently with the immigration raids and the targeting of perceived enemies during Mr. Trump’s second term.

“The America that represented wealth, freedom and institutional confidence feels like it belonged to a different era,” Mr. Wang said.

Among China’s foreign policy analysts, the conversation has turned to what Beijing can gain from the bilateral relationship, which has become more transactional under Mr. Trump than under President Joseph R. Biden Jr.

“Only China can save Trump,” said Huang Jing, a professor at Shanghai International Studies University, during a media event that was livestreamed in late 2025. With the U.S. midterm elections approaching, he argued, Mr. Trump needed visible wins such as Chinese purchases of American soybeans, corn and natural gas that could play well in swing states.

“Since Trump,” Mr. Huang said at the event, “the United States has become increasingly prone to compromise.”

Wu Xinbo, a leading American studies scholar at Fudan University, offered a similar assessment. If Republicans lose control of the House this fall, he said at the same event, Mr. Trump is likely to pivot toward his foreign policy legacy, creating space for a larger accommodation with Beijing.

China, he said, “should make good use of this opportunity.”

The war in Iran has reinforced the view that China has the upper hand with Mr. Trump. At a conference in late April, Mr. Wu argued that the war reduced Washington’s leverage against China while increasing Beijing’s by consuming American military and diplomatic attention in the Middle East.

The logic helps explain why China’s official language regarding Mr. Trump has often been less hostile than it was regarding Mr. Biden. According to a project by the Tracking People’s Daily newsletter, which used artificial intelligence to analyze nearly 7,000 Chinese official statements since 2021, Mr. Biden was presented as a more systemic threat — so serious that Mr. Xi accused Washington of “encirclement and suppression,” unusually confrontational language for a Chinese leader.

By contrast, the study noted, “Trump’s transactionalism is something Beijing understands and can work with.”

Yet belief in U.S. decline has not translated into aggressive Chinese foreign policy, at least not the kind of overt geopolitical gamble that Russia made before invading Ukraine.

China has become more assertive, pressuring U.S. allies, expanding military activity around Taiwan and restricting rare-earth exports in response to Mr. Trump’s tariffs. But even as Beijing advances the idea of the decline of American power, it appears wary of directly confronting what many Chinese analysts describe as a still dangerous superpower.

Two factors play into this circumspection. First, many Chinese strategists believe Beijing can do better by sitting back while the Trump administration fumbles. Second, an unstable and distracted United States may also be a more unpredictable one.

Beijing’s export-dependent economy needs a stable international order to function. An erratic United States threatens that stability in ways a confident, predictable America never did, Zongyuan Zoe Liu, an economist at the Council for Foreign Relations, told me.

Mr. Xi “is getting the United States he always wanted,” she said, “and the America he most feared at the same time.”

Health Secretary Robert F. Kennedy Jr. has said little publicly about vaccines in recent months, at the behest of a White House worried that his unpopular stance will hurt Republicans in November’s midterm elections. But he has not abandoned his quest for evidence that they are unsafe.

Working behind the scenes, Mr. Kennedy is spearheading an intense push, across health agencies under his purview, for government scientists and federal data contractors to examine his long-held theory that vaccines are helping to fuel an epidemic of chronic disease, according to multiple people familiar with the effort.

They said the wide-ranging inquiry is a top priority for Mr. Kennedy, who sees vaccines as a “potential culprit” in various neurological and autoimmune disorders, including asthma and allergies. It resurrects research into a number of ideas Mr. Kennedy has espoused, including whether vaccines are linked to autism and whether thimerosal, a preservative that has largely been removed from vaccines in the United States but remains in some flu shots, is dangerous.

The effort is being led by Martin Kulldorff, a biostatistician and vaccine safety expert who rose in prominence during the pandemic as a critic of Covid restrictions and vaccine mandates, and is now the health department’s chief science and data officer.

Career scientists at the Food and Drug Administration and the Centers for Disease Control and Prevention are conducting the research alongside contractors who provide statistical expertise and access to millions of patient medical records. The initiative was described to The New York Times by six people who are close to it, all of whom insisted on anonymity because it is not public.

The work is raising alarms among some vaccine scholars and critics of Mr. Kennedy, who have long accused the secretary of cherry-picking data and misinterpreting studies to claim that vaccines are unsafe and to limit their use. They fear Mr. Kennedy will use the findings to further erode confidence in vaccines, which the World Health Organization estimates saved 154 million lives over the past half-century.

Mr. Kennedy, who came into office saying he would do nothing to discourage people from getting vaccinated, has already taken steps to scale back the number of vaccines children receive. Public health experts complain that by spending money on issues that have already been thoroughly studied, he is taking funds away from research that might answer the very questions he is asking, including what causes autism.

“It just demonstrates that no matter what the general tone is about vaccines, whether we talk about them or not, the secretary is going to continue to try and look at the data and analyze it in a way that will help support the conclusions that he’s already made,” said Dr. Daniel Jernigan, who oversaw vaccine safety at the C.D.C. until he resigned in August. “And that, to me, is a real problem.”

Andrew Nixon, a spokesman for Mr. Kennedy, said in a statement that the effort reflected President Trump’s dedication to advancing “gold-standard vaccine research” that will enable policymakers to “better understand vaccine safety and efficacy and to assess how vaccine exposure, timing and patterns affect health across the life span.”

Mr. Nixon said the work would “inform vaccine recommendations, address critical gaps identified by scientific and medical organizations, including the Institute of Medicine, and strengthen public trust in public health.”

He said the initiative also involved the National Institutes of Health and universities. It remains unclear what the effort will cost and whether it is supplanting other routine government vaccine surveillance.

A former plaintiff’s lawyer, Mr. Kennedy has long said that he wants to build a body of scientific evidence on the harms of vaccines and environmental exposures, which he believes are behind an epidemic of chronic disease. That evidence, he has said, will lay the groundwork for legal action.

“That’s how you really change policy,” Mr. Kennedy said in a podcast as a presidential candidate in 2024. He added, “I’m going to provide that enough science, sufficient science, on each one of these exposures and each one of these injuries, to show who’s causing what and hold them responsible in court.”

During a daylong meeting on the new vaccine research initiative in late February, officials from the Health Department and the C.D.C. gathered to discuss specific studies and methods, including a look at the overall effect of the childhood vaccine schedule. Representatives from major health systems such as Kaiser Permanente were also at the table, given their role in allowing the C.D.C. access to vast troves of data through its Vaccine Safety Datalink system.

As part of the new effort, Mr. Kennedy has tasked some government scientists with studying the health status of vaccinated children compared with those who were not vaccinated. Mr. Kennedy coauthored a book, “Vax-Unvax: Let the Science Speak,” calling for such studies, which he believes will prove harm from vaccines.

Researchers say that such comparison studies would be riddled with pitfalls. Vaccinated children are more likely to receive medical care than those who are unvaccinated, and are thus more likely to receive additional medical diagnoses that could be wrongly attributed to vaccines.

Mr. Kennedy is also asking for the group to undertake new studies looking at the link between vaccines and autism.

The project is also looking at the question of harm from thimerosal, a mercury-based vaccine preservative, according to people close to the effort. The preservative has been thoroughly studied and found to be unrelated to autism, but Mr. Kennedy has remained concerned about it, and has rescinded federal recommendations for flu vaccines that contain thimerosal.

Through the C.D.C. alone, the cost of the project is estimated at $40 million to $50 million, according to a person familiar with the matter.

The project is being overseen by Mr. Kennedy and Stefanie Spear, his closest adviser. Mr. Kennedy’s new senior counselor for public health, Dr. Sara Brenner, a veteran of the F.D.A. who has voiced skepticism of vaccines, is expected to propel the studies forward in her new role, according to people familiar with the plan.

The new vaccine initiative is not the first time the secretary has waged a behind-the-scenes effort to study vaccine safety. Last year, Mr. Kennedy faced significant pushback within federal agencies and from Congress when he deployed David Geier, whose vaccine research is considered deeply flawed, to dig into vaccine safety data to explore some of the secretary’s longstanding concerns.

Mr. Kennedy’s team put pressure on C.D.C. officials, including Dr. Jernigan, who delayed Mr. Geier. When Mr. Kennedy ousted Susan Monarez, the agency’s director, Dr. Jernigan and other C.D.C. leaders quit.

Within the C.D.C. and F.D.A., scientists have registered some relief that Dr. Kulldorff, a pioneer in methods to examine vaccine safety, is leading the new inquiry. He worked on research that was groundbreaking in 2009 to monitor the safety of the H1N1 flu vaccine as it was being rolled out. The team he worked with found a slightly elevated rate of Guillain-Barré syndrome, an autoimmune condition associated with some vaccines.

“Martin had been known for decades as a top-notch vaccine safety scientist,” said Daniel Salmon, a Johns Hopkins University vaccine researcher who worked with Dr. Kulldorff on a vaccine data system that predated one the F.D.A. now uses.

Some scientists who worked with Dr. Kulldorff in the past, though, wonder if the evenhanded biostatistician they once knew changed during the pandemic. They point to a federal document, coauthored by Dr. Kulldorff, justifying sharp limitations on vaccines recommended to children in the United States, saying it left out reams of studies supporting flu and hepatitis B vaccines for infants and children.

In 2024, Dr. Kulldorff joined Mr. Kennedy in litigation against Merck, the makers of Gardasil, a vaccine for the human papilloma virus, earning $400 per hour as an expert witness, court records show. Merck, the vaccine’s maker, challenged Dr. Kulldorff’s standing as an expert based on his prior research finding that the vaccine was safe.

Dr. Kulldorff did not respond to a request for comment, and the health department did not respond to a request to make him available. Mr. Kennedy and Ms. Spear also did not respond to requests for comment.

The C.D.C. and the F.D.A. already devote considerable effort to investigating vaccine safety, using a number of databases and research methods. But Mr. Kennedy’s fellow vaccine critics, including Retsef Levi, a mathematician at the Massachusetts Institute of Technology who serves on Mr. Kennedy’s handpicked a panel of C.D.C. vaccine advisers, find fault with the current studies.

“Many of them have serious methodological flaws,” Dr. Levi said.

Mr. Kennedy began raising questions about vaccines’ safety about 20 years ago, and became a champion for mothers of children with autism who blamed the condition on vaccines. People familiar with his thinking say he still feels deeply committed to those women, and cannot reconcile their often heartbreaking stories with the vast body of research that discounts a link.

For parents who believe vaccines have harmed their children, Mr. Kennedy is fulfilling a major promise. Katie Wright, whose 24-year-old son has autism and got to know Mr. Kennedy through her advocacy for parents who question the safety of vaccines, said more research is necessary to restore trust in childhood immunization.

“There’s been tremendous pushback; they say, ‘Well, the research has been done.’ ” Ms. Wright said. “Well, you know what? A lot of families are concerned. I don’t understand the fear of delving deeper into safety research.”

As health secretary, Mr. Kennedy has demonstrated an unorthodox view of what makes for reliable findings about vaccines. He dismissed a major vaccine study of 1.2 million Danish children over 24 years as “a deceitful propaganda stunt,” for failing to highlight a subset of about 50 children who were more likely to have gotten Asperger’s syndrome, a diagnosis previously applied to high-functioning people with autism, after getting vaccines.

In the language of vaccine science, such findings are considered a signal to be examined in more depth. Dr. Kathryn Edwards, a Vanderbilt University expert in vaccinology, said she was concerned that selective attention to such signals could be “used to further erode the confidence that people have in vaccines.”

Mr. Kennedy has also made hasty changes to vaccine policy, often with minimal scientific justification for decision making. Among those pivots was an overhaul in January of vaccine recommendations, reducing the number of immunizations for American children to 10 from 17.

Though the plan was held up in court, Dr. Edwards said it portends a scenario where the findings of the current effort get a big splash in the media or drive new policies before scientists can understand the reasoning.

“What they’ve done is also worrisome,” she said, “because there have been so many things that haven’t been open and transparent.”