What many political historians will tell you is that Donald Trump‘s brand of politics was not created in a vacuum.

And most will point to an ad during George H.W. Bush‘s 1988 presidential campaign as the progenitor of dog-whistle political ads.

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That’s when Lee Atwater, a campaign advisor to Bush who died Friday at the age of 94, ran a TV ad that featured a mugshot of Willie Horton that tapped into white fears of Black crime and ushered in a new era in politics with the coded racist language that Trump is known for today.

The ad was intended to strike at Democrats for being soft on crime. Horton, a convicted murderer, escaped from a weekend furlough and went on to rape a woman and stab her fiancé in a brutal 1987 home invasion, according to Vox. The ad was widely condemned for playing on racial fears and equating black people with depraved acts. The ad remains the flashpoint for dog whistle politics.

Bush would go on to win the 1988 election over Michael Dukakis but would only be a one-term president. He presided over the end of the Cold War and will be remembered for his bipartisanship, his fairness, and for pushing for a “kindler, gentler America.” He will also be remembered for that Willie Horton ad and how it achieved what it was designed to achieve, which was to send a coded racist appeal to white voters.

Although Bush was staunchly against Trump and said he even voted for Hillary Clinton in the 2016 presidential election, history books will certainly include the impact of the Willie Horton ad—not just to win elections, but to do so at any cost.

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In 2014, Jonathan Chait captured the Horton debacle best in a New York Magazine article, in which he essentially said in spite of all the good Bush did as president, that “brutal, low campaign” of 1988 was something liberals could never forgive — and which Bush could never escape.