Donald Trump’s father was arrested at a Klan riot.

Most of the national media studiously avoided printing that simple declarative sentence since Donald Trump decided to run for president. Most of the country’s politicians have remained strangely silent on the topic.

Public commentators did not connect the dots even as President-elect Trump attacked the civil rights hero, John Lewis, when having a Klan sympathizer for a father would seem to be highly pertinent in explaining his behavior.

Yet the factual evidence seems strong. Trump’s father Fred was arrested in New York City in 1927, when a group of Klansmen got into a brawl with police officers during a Memorial Day parade in Queens. There is a document trail, and the names, dates, and addresses match up. The New York Times published a story about the riot and the seven men who were arrested; Fred Trump is mentioned by name. His address is given at 175-24 Devonshire Road, Jamaica, New York City, and the federal census of 1930 shows that Fred Trump resided at that address. The newspaper does not identify him as a Klan member, or clarify whether he was wearing a Klan robe—as were many of the demonstrators―but he did get arrested, and all seven men were represented by the same attorneys. Two days after the brawl, Fred Trump was discharged from custody, with no explanation that can be discovered from public records. The Times further reported that a police commissioner planned to investigate the Klan riot.

After the website Boing Boing reported the story in 2015, Donald Trump denied it, and he has not publicly discussed it since then.

The New York Daily News, the Washington Post, the New York Times and a few other news outlets mentioned the connection briefly in 2016, and then they dropped it. Throughout the campaign, most of the media maintained a deafening silence, as did most of the nation’s politicians in both parties. If Fred Trump was a full-fledged Klansman, no one seemed interested in pursuing the story. A diligent researcher might have at least tried to find the commissioner report in the city archives. Journalists and politicians displayed the most determined zeal in investigating every aspect of Hillary Clinton’s email in 2016, and 20 years ago they showed the same zeal in investigating the Clintons’ investment in Whitewater.

Yet the family history of the Republican Party’s nominee merited nothing close to that scrutiny. And this is the immediate family, the man’s own father, not some distant ancestor from another century, a father with the power to shape the boy’s most profound assumptions about the world. Moreover, Donald Trump has often expressed his admiration for his father. Thoughtful adults can hear the echoes of one hundred years ago in the president’s encouragement of violence at campaign rallies, his prejudices against minorities, and his use of violent language.

Historians know that the Ku Klux Klan, founded in Tennessee in 1866 by ex-Confederate officers, was created to intimidate black Southerners, especially those who wanted to vote, as well as the region’s ethnic and religious minorities. Since the 1860s, the Klan has spread all over the United States, with chapters in every region, and its targets have expanded to include immigrants, gays, and women who work outside the home. In the 1920s, the Klan grew dramatically in the cities of the North, often in response to the arrival of Catholics from Eastern and Central Europe. Accordingly, the Klansmen in Queens protested their presence in 1927 in New York City.

But in the public mind, the organization is still associated largely with the South. Perhaps that is one explanation for the silence on Fred Trump, Donald’s origins in the urban North. Maybe it is still too hard to face up to bigotry and prejudice anywhere outside the South.

We can easily imagine what would have happened if there had been the faintest rumor that Jimmy Carter, Bill Clinton, or Al Gore had a Klan sympathizer in the family—page one stories and protracted coverage in the media, politicians holding forth, bristling with the assumption that the allegation was probably true. Carter, Clinton, and Gore would have been judged unfit for public service, and their careers would have ended long before they reached national office.

Maybe there are other explanations for the silence about Fred Trump, beginning with shame, a deep embarrassment that the Klan has lasted so long and spread throughout the country, including New York. Perhaps it was the hope that the son would turn away from the spectre of a man who had been arrested at a Klan riot. Maybe it was the well-meaning but naïve belief that Donald Trump could not win the election.

Now he inhabits the White House. Let us hope that the country’s media and political leadership recover their usual probing interest in the President’s background, his motives, and his veracity. The future of the Republic may depend on it.