More than three years after he launched his campaign with an unprecedented tirade about Mexican criminals, drug mules, and rapists, Donald Trump is hoping to save the Republican House majority by returning to the nativist themes he believes won him the presidency. And, as he did in 2016, he is again pushing the limits of what passes for acceptable political discourse. On Thursday, in what is effectively his closing argument for the midterm election, Trump shared a new advertisement, produced by his campaign, that accuses Democrats of encouraging an invasion of violent immigrants and cop-killers to enter the United States illegally.

The ad, which was quickly condemned by Democrats, contains footage from the trial of Luis Bracamontes, who was sentenced to death this year for killing two police officers, smiling as he boasts that he will “kill more cops soon,” interspersed with video of the migrant caravan marching across Central America. In one clip, a translator relays to Fox News that a migrant is trying to escape justice. It closes with a question: “Who else would Democrats let in?”

The 53-second Web video is being compared to the infamous Willie Horton campaign ad, which appeared in the middle of the heated 1988 presidential election. That ad, which is frequently held up as the ne plus ultra of racist fear mongering in political advertising, highlighted a rape committed by Horton, a black man, after he was furloughed from prison under Massachusetts Governor Michael Dukakis, the Democratic presidential nominee. But of course, that ad was merely financed by supporters of the George H.W. Bush campaign. The Bracamontes ad, which is effectively the same tactic on steroids, with none of the subtlety, was developed by the Trump campaign and tweeted by the president himself.

The ad is the loudest in a series of racist dog whistles by the president in the closing weeks of the midterm election cycle. Last month, Trump explained that his campaign talking points would focus on “Kavanaugh; the caravan; law and order; and common sense.” But as Republican odds of holding onto the House have slipped, the president refined his message to focus on the most xenophobic elements animating the conservative base. In recent days, he ordered thousands of troops to defend the southern border, provoking accusations that he is using the U.S. military as a political prop. (“Increasing troops for a nonexistent crisis is a racist ploy and an irresponsible waste of resources,” Shaw Drake, policy counsel for the A.C.L.U., told The Guardian.) On Tuesday, Axios published an interview in which Trump discussed repealing birthright citizenship, a right enshrined in the 14th Amendment of the Constitution, which legal experts say would be impossible. The following day, pouring conspiratorial accelerant on the fire, he told reporters he “wouldn’t be surprised” if billionaire George Soros—a Jewish philanthropist who is an obsession of anti-Semites and was recently the target of a mail-bomb plot—was secretly funding the caravan. Throughout, his Twitter feed has remained a reliable dumping ground for random musings about the “very bad thugs and gang members,” as well as the “criminals and unknown Middle Easterners,” he claims are interspersed throughout the caravan.)