Foreword
Competition among countries will increase in the coming year as major powers and regional aggressors exploit complex global trends while adjusting to new priorities in US foreign policy. The risk of interstate conflict, including among great powers, is higher than at any time since the end of the Cold War. The most immediate threats of regional interstate conflict in the next year come from North Korea and from Saudi and Iranian use of proxies in their rivalry. At the same time, the threat of state and nonstate use of weapons of mass destruction will continue to grow.

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Iran and the Joint Comprehensive Plan of Action 
Tehran's public statements suggest that it wants to preserve the Joint Comprehensive Plan of Action because it views the JCPOA as a means to remove sanctions while preserving some nuclear capabilities. Iran recognizes that the US Administration has concerns about the deal but expects the other participants—China, the EU, France, Germany, Russia, and the United Kingdom—to honor their commitments. Iran’s implementation of the JCPOA has extended the amount of time Iran would need to produce enough fissile material for a nuclear weapon from a few months to about one year, provided Iran continues to adhere to the deal’s major provisions. The JCPOA has also enhanced the transparency of Iran’s nuclear activities, mainly by fostering improved access to Iranian nuclear facilities for the IAEA and its investigative authorities under the Additional Protocol to its Comprehensive Safeguards Agreement.

Iran’s ballistic missile programs give it the potential to hold targets at risk across the region, and Tehran already has the largest inventory of ballistic missiles in the Middle East. Tehran’s desire to deter the United States might drive it to field an ICBM. Progress on Iran’s space program, such as the launch of the Simorgh SLV in July 2017, could shorten a pathway to an ICBM because space launch vehicles use similar technologies. 

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Iran will develop military capabilities that threaten US forces and US allies in the region, and its unsafe and unprofessional interactions will pose a risk to US Navy operations in the Persian Gulf

Iran continues to develop and improve a range of new military capabilities to target US and allied military assets in the region, including armed UAVs, ballistic missiles, advanced naval mines, unmanned explosive boats, submarines and advanced torpedoes, and antishipand land-attack cruise missiles. Iran has the largest ballistic missile force in the Middle East and can strike targets up to 2,000 kilometers from Iran’s borders. Russia’s delivery of the SA-20c SAM system in 2016 has provided Iran with its most advanced long-range air defense system.

Islamic Revolutionary Guard Corps (IRGC) Navy forces operating aggressively in the Persian Gulf and Strait of Hormuz pose a risk to the US Navy. Most IRGC interactions with US ships are professional, but as of mid-October, the Navy had recorded 14 instances of what it describes as “unsafe and/or unprofessional” interactions with Iranian forces during 2017, the most recent interaction occurring last August, when an unarmed Iranian drone flew close to the aircraft carrier USS Nimitz as fighter jets landed at night. The Navy recorded 36 such incidents in 2016 and 22 in 2015. Most involved the IRGC Navy. We assess that these interactions, although less frequent, will continue and that they are probably intended to project an image of strength and, possibly, to gauge US responses.

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