In his first tweet early Wednesday, U.S. President Donald Trump proclaimed his bullish view of the American economy. The next three, sent minutes later, took him into alarming territory for a modern U.S. leader.
Mr. Trump retweeted three unverified anti-Muslim videos promoted by a British far-right fringe party. The videos had no apparent link to the United States and were united by their bigotry: They purported to show a Muslim migrant beating a Dutch boy on crutches, a group of Muslims throwing a man off a roof and a Muslim man smashing a statue of the Virgin Mary.
Mr. Trump's use of his presidential platform to embrace anti-Muslim prejudice has no precedent among modern presidents, experts say. The material was striking both in its discriminatory content and also its dubious origin: No American leader before him has publicly trafficked videos from obscure corners of the internet.
The retweets earned a sharp and unusual rebuke from British Prime Minister Theresa May, whose spokesman said that Mr. Trump's actions were "wrong." Britain First, the group which originally tweeted the videos, uses "hateful narratives" to "peddle lies and stoke tension," the Prime Minister's spokesman said.
Mr. Trump then fired back via Twitter, telling Ms. May she should instead turn her attention to terrorism and that "we are doing just fine."
Mr. Trump is "clearly telling members of his base that they should hate Islam and Muslims," said Nihad Awad, executive director of the Council on American-Islamic Relations, in a statement. "These are actions one would expect to see on virulent anti-Muslim hate sites, not on the Twitter feed of the president of the United States."
The White House press secretary brushed off evidence that one of the videos did not show what it claimed (the attacker filmed punching and kicking the boy on crutches was not a migrant but born in the Netherlands). "Whether it's a real video, the threat is real," said Sarah Huckabee Sanders on Wednesday. Mr. Trump's "goal is to promote strong border security and strong national security."
Historians struggled to name any parallel for Mr. Trump's actions in modern presidential politics. President Richard Nixon gave free rein to his prejudices against Jews and African-Americans in private, but did not voice them in public. Prior to becoming president, Franklin Delano Roosevelt wrote articles describing his repugnance at the idea of Japanese immigrants coming to the United States and intermarrying with Americans. Then he presided over the internment of more than 100,000 Japanese-Americans during the Second World War.
But he did not use the platform of his presidency to stoke prejudice, said Greg Robinson, a historian at the University of Quebec and the author of a book on FDR's internment of Japanese-Americans. Mr. Trump's open embrace of anti-Muslim views "is without precedent" in the modern era, Prof. Robinson said. "I can't think of any other time that a president publicly endorsed prejudice against a minority."
During his campaign to win the presidency, Mr. Trump called for a "total and complete shutdown" of Muslims entering the United States and declared that "Islam hates us." In January, he signed an executive order banning the citizens of seven Muslim-majority nations from the United States. The ban was struck down by U.S. judges and withdrawn; the two subsequent iterations also faced legal challenges but were partially implemented.
On Wednesday, Mr. Trump's sharing of anti-Muslim videos earned him plaudits from David Duke, a former leader of the Ku Klux Klan. Mr. Trump is "condemned for showing us what the fake news media WON'T," wrote Mr. Duke on Twitter. "Thank God for Trump! That's why we love him!"
According to the latest figures available from the U.S. Federal Bureau of Investigation, hate crimes in the United States rose in 2016 for the second year in a row, including an increase in crimes motivated by hatred of a particular religion. Roughly half of such crimes targeted Jews and a quarter targeted Muslims. Mr. Trump's actions Wednesday "are putting the lives and safety of American Muslim children and families at risk," said Mr. Awad of CAIR at a news conference Wednesday afternoon. "Hate speech leads to hate crimes."
Experts said that Mr. Trump has discarded any notion that what the U.S. president says should be vetted for accuracy or potential global impact. Mr. Trump's statements are "focused on his interpretation of what his followers want to hear, regardless of the effect on America's international reputation or the many Americans who don't support him," said Timothy Naftali, a presidential historian at New York University. "It's deeply irresponsible to use his enormous platform to promote religious intolerance."
Instead of relying on the many sources of expertise available to him as President, Mr. Trump prefers to rely on his own instincts. "What we're seeing is, if something is plausible to the President, then the President feels comfortable sharing it," said Kathleen Hall Jamieson, an expert on political communication who directs the public policy centre at the University of Pennsylvania. "And the President's plausibility filter is badly broken."