NEW YORK (AP) – Tony Schwartz, who helped create the infamous “daisy ad” that ran only once during the 1964 presidential race but changed political advertising forever, has died.

Schwartz, 84, died Sunday at his Manhattan home, said his daughter Kayla Schwartz-Burridge. He had been suffering from heart valve stenosis.

Schwartz, who started his career as a graphic designer, collaborated with a team from the Doyle Dean Bernbach ad agency to create the spot featuring a little girl counting aloud as she removed the petals of a daisy.

The scene then changed into a countdown to an atomic blast. President Lyndon B. Johnson, the Democratic incumbent seeking re-election, did the voiceover with the line, “We must either love each other, or we must die” – a paraphrase of a famous W.H. Auden poem written to mark the start of World War II.

The ad made no mention of Johnson’s Republican opponent, Arizona Sen. Barry Goldwater, but the implication was clear. After public criticism, it was withdrawn.

Johnson went on to win re-election, and the spot has been credited with ushering in an era of negative political ads.

Bill Geerhart, who runs a Web site called CONELRAD, a Cold War pop culture site, said the ad was a dramatic departure from the previous election cycle. “It’s light years ahead of that,” he said.

Schwartz worked on other campaigns, both for politicians and corporate clients like Coca-Cola and Chrysler. He also publicized the dangers of smoking in a series of commercials.

“He thought you could best influence people and best reach people by touching something in them,” Schwartz-Burridge said.

A ham radio enthusiast and a music lover, Schwartz spent time as a radio host and Broadway sound designer, and produced record albums including some using his own recordings.

The author of two books, he taught media studies at several universities. But because he suffered from agoraphobia, he relied on technology to teach from home.

His work was acquired by the Library of Congress in 2007.