The most effective ad ever made for a presidential election featured a violent, career-criminal, Willie Horton, walking out of a Massachusetts prison on a weekend pass. On one of those passes, he went on another vicious crime spree. George H. W. Bush used those crimes — and the lax policies that let Horton roam the country — to destroy his Democratic opponent, Massachusetts governor Mike Dukakis.

The past is prologue. Once again, voters are worried about their safety and angry about the open-border policies that have degraded it. Donald Trump knows that, so he will be using ads like the one Bush used against Dukakis. They will have the same devastating impact.

A little background is helpful. The 1988 ad (the video is here) was a searing attack on Dukakis’s lenient parole rules and his “soft on crime” policies, showing how they endangered the public. Willie Horton was a compelling example. He was serving a life sentence without the possibility of parole after stabbing a boy nineteen times during a robbery, killing him. Yet the Massachusetts prison system, under Dukakis’s leadership, repeatedly gave Horton passes to leave for the weekend.

What could possibly go wrong? Lots. On his tenth weekend pass, Horton chose not to return. He left the state and went on another brutal crime spree, committing armed robbery (again), assault and rape. Bush pinned those crimes on Dukakis and used the ad to highlight his sharp differences from the Massachusetts governor. It worked.