For several decades, the U.S. has sought to deter Iran from developing nuclear weapons. But ironically, the reason Iran has the technology to build these weapons in the first place is because the U.S. gave it to Iran between 1957 and 1979. This nuclear assistance was part of a Cold War strategy known as “Atoms for Peace.”

The strategy’s name comes from Dwight Eisenhower’s “Atoms for Peace” speech, given before the United Nations General Assembly in 1953. In it, he suggested that promoting the non-military use of nuclear technology could discourage countries from using it to create nuclear weapons, or “Atoms for War.”

The speech came only eight years after the invention of the atomic bomb, at a time when the U.S. was anxious to keep these new and frightening weapons from proliferating around the world. Strange as it sounds, President Eisenhower viewed his “Atoms for Peace” strategy partly as a form of arms control.

“He thought that sharing nuclear technology for peaceful purposes would reduce the incentives of countries to want to make nuclear bombs,” says Matthew Fuhrmann, a political science professor at Texas A&M University and author of Atomic Assistance: How “Atoms for Peace” Programs Cause Nuclear Insecurity. For example, countries can use nuclear technology to generate electricity through nuclear power plants or produce radioisotopes for medical purposes.

AUDIO: Eisenhower on Atomic Energy On December 8, 1953, President Dwight D. Eisenhower addresses the General Assembly of the United Nations on the peaceful use of atomic energy.

“The alternative, of course, was to just try and set up an international embargo that would restrict the transfer of any nuclear technology to any state that didn’t already possess it,” Fuhrmann says. However, Eisenhower feared an embargo would “make other countries want the technology more,” possibly increasing “their resolve to eventually get it and maybe use it for more sinister purposes.”

There was also another dimension to “Atoms for Peace.” Nuclear technology was something valuable and new, and it conferred a certain status on countries that had it. The U.S. viewed providing other countries with the technology as a means of gaining influence over those states and achieving political goals. To that end, the U.S. provided nuclear assistance to countries it wanted to influence, such as Israel, India, Pakistan, and Iran.

At the time, the U.S. was closely allied with Iran’s Shah, Mohammad Reza Pahlavi. So closely, in fact, that when Iran toppled the Shah’s monarchy and democratically elected a prime minister, the CIA staged a 1953 coup d’état that put the Shah back in power. Part of the reason the U.S. valued Iran as an ally was because of its strategic location bordering the Soviet Union. During the early part of the Cold War, the U.S. set up a base in Iran to monitor Soviet activity.

In this context, the United States’ nuclear cooperation with Iran “was, in part, a means to shore up the relationship between those countries,” Fuhrmann says. The cooperation lasted until 1979, when the the Iranian Revolution ousted the Shah and the U.S. lost the country as an ally.

All of the nuclear technology the U.S. provided Iran during those years was supposed to be for peaceful nuclear development. But the “Atoms for Peace” strategy ended up having some unintended consequences.

“A lot of that infrastructure could also be used to produce plutonium or weapons-grade, highly-enriched uranium, which are the two critical materials you need to make nuclear bombs,” Fuhrmann says. In effect, the U.S. laid the foundations for the Iranian nuclear weapons program.

Iran first became seriously interested in creating nuclear weapons during the 1980s Iran-Iraq War. It tried unsuccessfully to develop them in the late ‘90s and early 2000s. Still, Iranian nuclear development remains an international concern, especially now that Trump has withdrawn the U.S. from the 2015 Iranian nuclear deal, known as the Joint Comprehensive Plan of Action.

In the weeks leading up to Trump’s decision, Israeli Prime Minister Benjamin Netanyahu tried to convince him to exit the deal by arguing that Iran was still pursuing nuclear weapons. Other policy experts and world leaders have rejected this claim, and Fuhrmann says he’s seen no evidence that “Iran has violated the deal, or that Iran has done anything since 2003 … to build nuclear bombs.”

However, now that the U.S. has withdrawn from the nuclear deal, Fuhrmann worries “Iran is going to have incentives to do those things, whereas under the deal, those incentives were greatly reduced.”