Threats and assassination attempts come with the office Donald Trump once held and is seeking again

It turns out, records show, that threats come with the office that he once held and is trying to win again, and occur far more frequently than is widely known.

An examination of Syracuse University's Transactional Records Access Clearinghouse, known as TRAC, shows that since 1986 when Ronald Reagan was in the White House, the federal government has prosecuted 1,444 cases of threats against presidents or others in line of presidential succession.

The highest number of prosecutions in a single year came in 1987 during the Reagan years when there were 73. TRAC data shows there were 72 cases brought in 2002 during the George W. Bush administration. The Bush administration also had the highest number of cases over its eight-year span with 383, a time of heightened tension during the wars in Iraq and Afghanistan. Prosecutors brought 343 cases when Bill Clinton was president and 213 during former President Barack Obama's two terms. There were 68 cases brought in Trump's first term. Reagan had 200 in the last three years of his presidency and 213 cases were brought during George H.W. Bush's one term.

Authorities were continuing to examine Routh's potential motive and movements in the days and weeks leading up to Sunday, when a Secret Service agent assigned to Trump's security detail spotted a firearm poking out of shrubbery on the West Palm Beach golf course where Trump was playing. The agent fired, and Routh escaped into a sport utility vehicle, leaving behind a digital camera, a backpack, a loaded SKS-style rifle with a scope and a plastic bag containing food.

The attempt on Trump is unique because he is a former president seeking to regain the office who has now faced two attempts. But he is not the only former president who survived an assassination attempt trying to retake the office. Teddy Roosevelt was running as a former president in 1912 when he was shot in the chest while campaigning in Milwaukee.

''This is not unprecedented. People tend to forget how violence has been around the United States for a long time,'' said David Head, a historian at the University of Central Florida in Orlando.

There have been a number of notable instances that are not included in the TRAC data. Reagan was severely wounded in 1982 and then-President Gerald Ford had two attempts on his life in a 17-day period in 1975. George W. Bush was in Tbilsi, Georgia with Georgian president Mikheil Saakashvili in 2005 when someone rolled a hand grenade into the room that did not explode.

Clinton was in the White House on Oct. 29, 1994, when Francisco Martin Duran, then 26, opened fire outside and fired about 20 rounds at the building. No one was injured but Duran was convicted of attempting to assassinate the president and sentenced to 40 years. According to the Bureau of Prisons website, he is in a federal prison in Virginia and is not eligible for release until 2029.

In the summer of 1941, James F. Byrnes became a Supreme Court justice. Little over a year later, he had had enough and left the court to take a key role in planning the nation's wartime economy.