In what may be one of the biggest coincidences in presidential history, Abraham Lincoln signed legislation creating the Secret Service on April 14, 1865, just hours before he was assassinated. But the agency he created wouldn’t have done much to save him had they been around sooner. The original purpose of the United States Secret Service was to tackle the country’s burgeoning counterfeit money problem.
By the time LIFE covered the Secret Service more than a century later, it had taken on a dual mission--protecting the country's currency and protecting the President, other high-ranking officials and their families from bodily harm.
In 1968, five years after the assassination of President Kennedy, and in the month after Martin Luther King’s death and before Robert Kennedy’s, LIFE dispatched photographer Stan Wayman to shoot the men as they practiced their shooting. In this monthly qualification test, which agents had to pass in addition to biannual physical exams, agents were tested in marksmanship, motorcade etiquette, defensive combat and life-saving techniques.
Agents practiced shooting at the National Arboretum, which was, according to notes accompanying the photographs, “one of the few places in the District isolated enough to shoot guns without passers-by thinking another riot is taking place.” “Another” here refers to the six days of rioting that took place in Washington after King’s death the previous month. But everything that took place on this spring day was just a drill, and the few tourists who did spot the agents “were sadly disappointed to find out the president wasn’t along for the work out.”
Liz Ronk, who edited this gallery, is the Photo Editor for LIFE.com. Follow her on Twitter at @LizabethRonk.