It happened on a dreary March afternoon in 1981. President Ronald Reagan was leaving the Washington Hilton hotel after giving a speech to a union group when John W. Hinckley Jr. opened fire from his .22-caliber revolver.

At the sound of the gunshots, Secret Service agents swarmed, and one of them shoved the president into the waiting limousine — but not before one of the bullets struck home, hitting Reagan in his side.

What transpired over the next few hours became the stuff of presidential and political legend. The life of the 70-year-old president was saved by the quick actions of his lead Secret Service agent, as well as the skill of medical personnel at George Washington University Hospital. Reagan’s courage over those tense hours further cemented his relationship — and political standing — with the American public and changed the way he approached the job over the next eight years.

On the surface the parallels between 1981 and what happened Saturday in Butler, Pennsylvania, when a gunman fired shots at former President Donald Trump, are striking. A gunman got off several shots as Trump was addressing a rally crowd, and Trump was struck in the right ear. Trump ducked behind a lectern as agents piled on top of him as human shields. In what is sure to be an iconic moment, a bloodied Trump raised a defiant fist to the crowd as agents whisked the presumptive Republican presidential candidate off the stage.

“I knew immediately that something was wrong in that I heard a whizzing sound, shots, and immediately felt the bullet ripping through the skin,” he said in a statement.

Trump’s campaign said he was doing “fine” after being checked out at an area medical facility. Authorities are working to figure out what happened in Butler.

As the public learned in the hours after the Reagan assassination attempt, early reports can be wrong. Only much later did the public realize how close Reagan came to dying that day — his life had hung in the balance of a split-second decision and an inch.

It was just 70 days into Reagan’s first term when he left the Washington Hilton on March 30 after a speech to a trade union and approached his waiting limousine at 2:27 p.m. Hinckley couldn’t believe his luck. A troubled 25-year-old, Hinckley had been hoping to kill the president to impress actress Jodie Foster. He had now somehow found himself standing behind a rope line in a crowd of spectators and journalists — all unscreened by the Secret Service — just 15 feet from the president.

He pulled out his revolver and opened fire.

His first bullet struck White House Press Secretary James Brady in the head, and his second hit D.C. Police Officer Thomas Delahanty in the back.

At the sound of the shots, Secret Service Agent Jerry Parr grabbed Reagan and shoved him toward the open door of the armored limousine. Hinckley’s third bullet flew high. The fourth hit Secret Service Agent Tim McCarthy in the chest as he stood between the president and the gunman.

The fifth shot hit the armored window of the limousine. Hinckley’s final bullet ricocheted off the side of the limousine, flattening into the shape of a dime and striking Reagan five inches below his left armpit. Parr dove in behind the president, and the door slammed shut. Parr ordered the limousine to head to the White House.

Parr didn’t know Reagan had been shot. But when the president complained of pain in his chest and Parr noticed frothy blood on his lips, the agent ordered the limousine to head to George Washington University hospital. There, Reagan insisted on walking into the hospital under his own power but collapsed like a dead weight in the hallway.

Doctors and nurses located his wounds. They could not stem Reagan’s bleeding, however, forcing surgeons to operate to staunch it. Reagan lost more than half his blood volume that day before the bleeding was brought under control. Surgeons removed the bullet lodged just an inch from the president’s heart.

As laid out in my book, Rawhide Down: The Near Assassination of Ronald Reagan, the shooting generated massive sympathy from the American public for Reagan, who spent 13 days in the hospital before returning to the White House. But it did something else — it built a bond between the president and the public. They had seen a president who acted with grace and courage. They would hear that he had cracked jokes with his doctors and nurses as they fought to save his life and sought to ease the anxiety of loved ones.

Lying on a gurney in the trauma bay, a chest tube draining blood from his side, Reagan sought to calm down his wife, Nancy, with a quip.

“Honey, I forgot to duck,” he told her, borrowing a line that boxer Jack Dempsey delivered to his own wife after losing the 1926 heavyweight championship.

He joked with advisers as he was being wheeled into the operating room. And just before he was put under for surgery, he cracked to his surgeons: “I hope you are all Republicans.”

Dr. Joseph Giordano, a liberal Democrat, replied: “Today, Mr. President, we are all Republicans.”

The White House wasted little time in ensuring those lines were delivered to the press. As David Broder, a Washington Post political journalist, would write two days later: “What happened to Reagan on Monday is the stuff of which legends are made.”

Three decades later, Broder stood by that assessment. “He was politically untouchable from that point on,” Broder said in an interview. “He became a mythic figure.”