Confrontation between United States and Iran

"Blessed are the Peacemakers"

Recent Developments

Since the United States withdrew from the Joint Comprehensive Plan of Action (JCPOA) in May 2018, tensions have risen between the United States and Iran. While the Donald J. Trump administration pursues a strategy of maximum pressure to bring Iran to the negotiating table, Iran has begun to contravene the JCPOA’s restrictions on its nuclear program.

In April 2019, the United States designated Iran’s Islamic Revolutionary Guard Corps (IRGC) a terrorist organization—the first time the United States classified part of another government as such. In May 2019, after intelligence suggested Iran and its militias were preparing to attack U.S. troops in Iraq and Syria, the United States deployed B-52 nuclear-capable bombers, an aircraft carrier strike group, and additional Patriot missile batteries to the Middle East to deter Iran. The same week, Iran announced a sixty-day deadline for sanctions relief before exceeding the JCPOA’s cap on uranium enrichment levels and later threatened to exceed uranium stockpile limits.

Also in May 2019, following a rocket attack on Baghdad’s Green Zone in Iraq—which U.S. defense officials blamed on Iran—and the release of images of missiles on IRGC boats in the Persian Gulf that U.S. intelligence officials cited as signs of a growing Iranian threat, nonemergency U.S. government employees were evacuated from Iraq. Over the next month, six oil tankers in or near the Strait of Hormuz were attacked, which U.S. government officials have also blamed on Iran, and the United States deployed an additional 2,500 troops to the Middle East. Escalating military tension has been matched by increasingly bellicose rhetoric from government officials. In June, Iranian Foreign Minister Javad Zarif warned that the United States “cannot expect to stay safe,” and President Trump cautioned that there’s “always a chance” of war with Iran.

Tensions peaked in late June 2019 after Iran downed a U.S. Global Hawk drone in the Strait of Hormuz. In response, President Trump approved—and quickly canceled—a retaliatory strike, instead ordering a cyberattack on the IRGC and Iran’s missile systems and imposing new sanctions on Iranian Supreme Leader Ali Khamenei and top Iranian military commanders. Secretary of State Mike Pompeo and other U.S. government officials briefed Congress on Iran’s ties with al-Qaeda, raising concerns from Congressional leadership that President Trump would approve a war with Iran by citing the 2001 Authorization for Use of Military Force, which grants the president authority to target al-Qaeda and countries supporting the group. On July 1, 2019, Iran exceeded the JCPOA’s cap on uranium stockpiles. Later in July, the United States downed an Iranian drone in the Strait of Hormuz after the drone approached a U.S. Navy ship.


Forty years after the 1979 Iranian Revolution, relations between the United States and Iran are as tense as they have ever been. As Iran advances its nuclear program and trains proxy forces throughout the Middle East, the potential for conflict continues to increase.

Iran has pursued a nuclear program since at least 1957, with varying degrees of success. By the late 1980s during a brutal war with Iraq, Iran decided to develop nuclear weapons to ensure its security and, consequently, Iran pursued nuclear agreements with China and Russia throughout the 1990s to support its ongoing research into the development of nuclear weapons. Under growing scrutiny and international pressure, in 2003-04 Iran agreed to terminate its nuclear weapons program, insisting only that it maintain its nuclear centrifuges for nuclear energy. However, the International Atomic Energy Agency (IAEA) discovered and exposed that Iran had continued to pursue nuclear weapons later in 2003 and a coalition of countries known as the P5+1—the United States, China, France, Germany, Russia, and the United Kingdom—began a series of negotiations in an effort to constrain Iran’s nuclear program and prevent the development of nuclear weapons. To encourage Iran to cease uranium enrichment and come to the negotiating table, the UN Security Council imposed economic sanctions on Iran in 2006. The sanctions resulted in 20 percent domestic unemployment and a severe contraction of Iran’s gross domestic product, which in part enabled Hassan Rouhani to win Iran’s presidential election in 2013—he campaigned on promises to lift sanctions and restore the economy.

Over the next two years, the United States convened several rounds of bilateral talks and led the P5+1 in negotiations with Iran, which resulted in official agreement on the JCPOA in 2015. Once key parties had signed the agreement, the UN Security Council approved resolution 2231, which paved the way for sanctions relief. The JCPOA requires Iran to reduce its stockpile of enriched uranium by 98 percent for fifteen years, cut the number of operating centrifuges by two-thirds for ten years, and provide International Atomic Energy Agency (IAEA) inspectors access to enrichment facilities within twenty-four days if the IAEA suspects violations. Moreover, if the IAEA confirms violations, the JCPOA allows for the immediate reinstatement of sanctions. After the JCPOA entered into force on January 16, 2016, Iran received sanctions relief that totaled nearly $100 billion.

Though Iran’s nuclear ambitions were restricted by the JCPOA, Iran’s regional ambitions continued to grow. Iran has continued to arm and train Shiite militants through its Quds Force—the IRGC’s international arm—which has led to sectarian divisions. The Quds Force has provided advanced armed drones to Hezbollah in Lebanon, trained and funded more than one hundred thousand Shiite fighters in Syria, supplied ballistic missiles and drones to Yemen’s Houthis, and helped Shiite militias in Iraq build missile capabilities. The U.S. government considers Iran to be the foremost state sponsor of terrorism—spending more than one billion dollars on terrorist financing annually—and there are between 140,000 and 185,000 IRGC-Quds Force partner forces in Afghanistan, Gaza, Lebanon, Pakistan, Syria, and Yemen.

Iran has also continued to develop ballistic missiles, which, according to the United States, violates UN resolution 2231. In response, the United States continues to impose sanctions on Iran’s ballistic missile program and the IRGC through the Countering Iran’s Destabilizing Activities Act of 2017 and the Countering America’s Adversaries Through Sanctions Act.

Because the JCPOA only addressed Iran’s nuclear program—and not its revisionism or ballistic missile programs—the Trump administration asserted that the agreement was a stopgap. Thus, in May 2018, President Trump withdrew the United States from the JCPOA, pledging to seek a more comprehensive deal. Secretary of State Mike Pompeo subsequently issued twelve requirements for a new agreement, which Iranian Supreme Leader Ali Khamenei responded to by proposing seven conditions for remaining in the JCPOA. Since May 2018, the Trump administration has reimposed and raised new sanctions against Iran and demanded that European countries withdraw from the JCPOA as part of a new containment strategy. France, Germany, and the United Kingdom refused to do so and have since attempted to devise a backchannel for trade with Iran; the Trump administration responded by threatening European allies and European companies with consequences should they continue to do business with Iran. Iran’s oil exports have since decreased by more than half. U.S. sanctions have sparked the worst economic crisis Iran has faced in forty years and emboldened Iranian hardliners.


A worsening conflict with Iran would have significant economic, political, and security implications for the United States. Should the United States and Iran engage in military conflict, Iran could attempt to block the Strait of Hormuz, through which 30 percent of the world’s oil flows, which would raise oil prices globally. Moreover, the United States risks isolating itself from already beleaguered allies: in June 2019, NATO refused to commit to working with the United States to secure freedom of navigation in the Strait of Hormuz. A U.S.-Iran confrontation could trigger an escalation of proxy warfare in countries like Syria and Yemen, or an increase in Iranian missile strikes targeting the seventy thousand U.S. troops in the Middle East.

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