Presidential hopefuls burn bright, then fade. Poll numbers rise and fall. Presidents pass the torch; administrations change. Through it all, one constant remains: The Associated Press’ coverage of the American president.

Ever since Zachary Taylor and the Whig Party won the White House more than 150 years ago, AP reporters and photographers have been the dominant source of presidential news for media across the U.S. and around the world.

Much of what we know about President Abraham Lincoln’s masterpiece, the Gettysburg Address, comes from the hand of AP statehouse stenographer Joseph I. Gilbert, who alone transcribed Lincoln’s original text. Pioneering AP Washington correspondent Lawrence Gobright accompanied Lincoln on horseback to the telegraph office for the latest updates on Civil War battles, and broke the news of the president’s assassination. As President James Garfield lay dying in the White House from an assassin’s bullet, AP reporter Franklin Hathaway Trusdell listened in at the bedroom door for the sound of breathing from the mortally wounded president. Garfield soon succumbed at his summer home in New Jersey.

Since AP launched its WirePhoto service in 1935, the news cooperative has been no less committed to photographic coverage of the White House. AP photographers accompany the president everywhere. Wearying routine and photo ops can yield in an instant to breaking news that moves the world and dominates front pages, broadcasts and websites.

AP photographer Ron Edmonds was focused on President Ronald Reagan as the president walked to his limousine after a 1981 speech in Washington. As Reagan waved to onlookers, Edmonds heard strange pops and held his motor drive shutter down. Edmonds’ exclusive photos of the assassination attempt earned him the Pulitzer Prize, one of four Pulitzers won by AP photographers for their coverage of the presidency.

For the journalists of the world’s leading news agency, the mandate of covering the White House remains the same as it was in Lincoln’s day: be accurate, be fair and be fast. For photographers, who can never catch up to a missed opportunity, it also means this rule: Never take your camera off POTUS (President of the United States).

The photos in this exhibition are drawn from the AP Images photo archive, which contains more than 20 million film and digital images, and is one of most extensive collections of news and documentary images anywhere.