Donald Trump has done more than any political figure in the United States to propagate the beliefs and court the support of the white supremacist* "alt-right" movement, whose adherents held a rally in Charlottesville, Virginia, on Saturday, where a white supremacist named James Fields Jr. killed a nonviolent protester named Heather Heyer with his car. Here's an attempt at a comprehensive list of the ways Trump has promoted and benefited from the movement.
Birtherism. Trump began insisting in 2011 that Barack Obama may not have been born in the United States. He once said a "very credible source" had informed him that Obama's birth certificate was fraudulent and claimed to have sent investigators to Hawaii to research the matter. Trump has also suggested Obama may be a Muslim who is sympathetic to the goals of groups like ISIS. (Obama is an American-born Christian.)
Steve Bannon. The former chairman of Breitbart News helped run Trump's campaign and is a senior White House adviser. Bannon once proudly described Breitbart as "the platform for the alt-right," and under his leadership the site published an infamous article that celebrated the work of several white supremacists, including Richard Spencer, who was one of the leaders of the Charlottesville rally and who made headlines for using Nazi slogans and gestures at a Washington celebration of Trump's inauguration. (Breitbart also famously posted some of its stories under the heading "Black Crime.") Bannon has repeatedly and publicly endorsed The Camp of the Saints, a novel popular in white-pride circles in which black Americans, "dirty Arabs," and feces-eating Hindu rapists (among others) destroy civilization. The book refers to black individuals as "niggers" and "rats." Bannon has also reportedly praised a far-right French writer named Charles Maurras who was sentenced to life in prison after World War II for collaboration with Nazi occupiers. And he's complained publicly that too many tech CEOs are Asian American. And he reportedly told his ex-wife that he didn't want their children attending schools with significant Jewish enrollment.
Milo Yiannopoulos. The Nazi-fetishizing former Breitbart staffer who co-wrote the white-supremacist article described above can thank Bannon, who has called his work "valuable," for launching his career. Trump’s first national security adviser, Michael Flynn, called Yiannopoulos "brave" and said he was a "phenomenal individual" in November 2016. In February of this year, Trump himself tweeted a threat to revoke the University of California at Berkeley's federal funding because it canceled Yiannopoulos' appearance on campus. Yiannopoulos subsequently resigned from Breitbart during a furor over approving remarks he made in 2016 about pedophilia—but it appears that his career is still being funded by Robert Mercer, a right-wing billionaire whose daughter Rebekah served on Trump's transition team.
Alex Jones. Jones' site InfoWars advocates paranoid beliefs of all sorts, including but not limited to alt-right-adjacent theories about the "Jewish mafia" and "globalists," such as the Rothschilds, who manipulate world events to enrich themselves. Trump called Jones "amazing" during a 2015 interview, and the White House seemingly confirmed to the New York Times that Trump and Jones occasionally speak on the phone.
Sebastian Gorka. Ostensibly a counterterrorism adviser, Gorka’s job appears to consist entirely of making grandiose and factually erroneous declarations during Fox News appearances, and he is reportedly a member of a far-right Hungarian group called Vitézi Rend that collaborated with the Nazis during WWII. (He denies it.)
Julie Kirchner. Previously the executive director of the Federation for American Immigration Reform, Kirchner was appointed to work at the federal Office of Citizenship and Immigration Services by the Trump administration in May. The Federation for American Immigration Reform's founder and its current president are both interested in eugenics and crank race science; both have complained that immigration undermines whites' dominance.
Social media outreach. Trump conducted an exclusive Q&A in July 2016 with a notorious Reddit forum called The_Donald. The first question he answered was submitted by Milo Yiannopoulos, and another user whose question he answered had previously referred to Black Lives Matter protests as "chimp outs." Other threads on The_Donald prior to Trump's Q&A had covered such subjects as "race mixing," Nazis' allegedly high IQs, and the "Jewish influence" in America. Top Trump aide Dan Scavino is essentially a White House liaison to internet extremists, while Donald Trump Jr. has retweeted prominent white supremacists and conducted an interview with a white-supremacist radio host who has said that interracial relationships constitute "white genocide." Trump Sr., for his part, famously retweeted a Twitter user named "WhiteGenocideTM" and posted an anti-Semitic Hillary Clinton meme image created by a Twitter user whose other work involved grotesque caricatures of black and Jewish individuals.
Saying and doing racist things constantly. During the 2016 campaign, Trump attacked a federal judge who had prosecuted drug traffickers in a previous job by calling him "Mexican" (he was born in Indiana) and suggesting that he was sympathetic to Mexican cartels; asserted that Mexican immigrants are disproportionately likely to commit rapes; defended the internment of Japanese Americans during WWII; retweeted a hoax graphic that wildly overstated the rates at which black Americans commit crimes against whites; claimed incorrectly that Oakland is one of the most dangerous cities in the world; suggested that bereaved miitary father Khizr Khan supports Islamic terrorism; reiterated his belief that the Central Park Five are guilty despite their having been legally exonerated; and approvingly repeated an apocryphal story about an American officer putting down an insurrection in the Philippines by executing Muslims using bullets dipped in pigs' blood.
NBC News tracked down alleged Charlottesville killer James Fields Jr.'s mother on Sunday. She told the network that she hadn't known that her son was attending a white supremacist event. "I thought it had something to do with Trump," she said. Indeed.
*Note on nomenclature: I'm using the term white supremacist in some cases where others might use white nationalist. The self-identification distinction between the two groups is that many white nationalists claim that they believe the United States should be a culturally and politically white-dominated society because it has historically been so, not because whites are intrinsically superior. An avowedly white U.S. "ethnostate," though, is still one in which whites would maintain supremacy over nonwhites, so I believe white supremacist applies broadly. Also, regardless of what they may claim, many self-identified white nationalists are quite obviously racially prejudiced against nonwhites.