Political assassinations in the United States have a long and disturbing history.

The attempted assassination of Donald Trump, who narrowly escaped death when a bullet grazed his right ear while he was speaking at a campaign rally in Pennsylvania on Saturday, highlights the danger of those seeking votes in a country whose constitution guarantees citizens the right to bear arms.

Trump joins a not-so-exclusive club of U.S. presidents, former presidents and presidential candidates who have been the target of bullets. Of the 45 people who have served as president, four have been assassinated while in office.

Given the near mythic status of U.S. presidents, and the nation’s superpower role, political assassinations strike at the very heart of the American psyche.

Abraham Lincoln’s killing in 1865 and that of John F. Kennedy in 1963 are key moments in the history of the United States. James Garfield (1881) and William McKinley (1901) are less remembered, but their deaths nonetheless rocked the nation at the time.

Secret Service provides protection

It was after McKinley’s assassination that the U.S. Secret Service was given the job of providing full-time protection to presidents.

The last American president to be shot was Ronald Reagan, who was seriously wounded and required emergency surgery in 1981.

Reagan was leaving a Washington hotel after giving a speech when gunman John Hinckley Jr. fired shots from a .22-calibre pistol. One of the bullets ricocheted off the president’s limousine and hit him under the left armpit. Reagan spent 12 days in hospital before returning to the White House.

Other presidents have been shot at, but luckily, not injured.

In 1933, a gunman fired five shots at the car of then President-Elect Franklin D. Roosevelt. Roosevelt wasn’t hit but the mayor of Chicago, Anton Cermak, who was speaking to Roosevelt after the newly elected president had made some brief remarks to the public, was injured and died 19 days later.

Two attempts in one month

In September of 1975, President Gerald Ford survived two separate assassination attempts — both by women. The first came on Sept. 5 when Lynette (Squeaky) Fromme, a follower of cult leader Charles Manson, tried to shoot Ford as he was walking through a park in Sacramento, Calif., but her gun misfired and didn’t go off. On Sept. 22, Sara Jane Moore, a woman with ties to left-wing radical groups, got one shot off at Ford as he left a hotel in San Francisco but it missed the president.

Presidential candidates have not been exempt from assassination attempts, including most notably Senator Robert F. Kennedy killed in 1968 and George Wallace shot and left paralyzed in 1972.

In 1912, former president Theodore Roosevelt was hit in the chest by a .38-calibre bullet as he was campaigning to regain the White House. But most of the impact of the bullet was absorbed by objects in the chest pocket of Roosevelt’s jacket. Even though he had been shot, Roosevelt went on to make a campaign speech with the bullet still in his chest.

The violence of 1968

Other figures with significant — if unelected — political power have also had their lives cut short by gunfire, most notably Martin Luther King Jr. in 1968, just a few months before Bobby Kennedy’s death.

In a country with more guns than people, and with firearms easily available, it is not surprising that invariably shootings are the preferred means of killing or attempting to kill political office holders.

Like Trump, most assassination attempts occur when candidates and politicians are in public spaces with crowds of people nearby. There is a long history of politicians insisting, against the advice of their security advisers, to “press the flesh” in events that jeopardize their safety. Trump was extraordinarily fortunate to escape with only minor injuries.

By Professor Thomas Klassen, School of Public Policy and Administration, York University

This article is republished from The Conversation Canada.