Since May 2019, U.S.-Iran tensions have escalated. The Trump Administration, following its 2018 withdrawal from the 2015 multilateral nuclear agreement with Iran (Joint Comprehensive Plan of Action, JCPOA), has taken several steps in its campaign of applying "maximum pressure" on Iran. Iran and Iran-linked forces have targeted commercial ships and infrastructure in U.S. partner countries. U.S. officials have stated that Iran-linked threats to U.S. forces and interests, and attacks on several commercial ships in May and June 2019, have prompted the Administration to send additional military assets to the region to deter future Iranian actions. However, Iran's downing of a U.S. unmanned aerial aircraft might indicate that Iran has not been deterred, to date. President Donald Trump has said he prefers a diplomatic solution over moving toward military confrontation, including a revised JCPOA that encompasses not only nuclear issues but also broader U.S. concerns about Iran's support for regional armed factions. During May-June 2019, the Administration has placed further pressure on Iran's economy. By expanding U.S. sanctions against Iran, including sanctioning its mineral and petrochemical exports, and Supreme Leader Ali Khamene'i. Iranian leaders have refused to talk directly with the Administration, and Iran has begun to exceed some nuclear limitations stipulated in the JCPOA. High-ranking officials from several countries, including Japan, Germany, France, Oman, Qatar, and Iraq, have visited Tehran to try to de-escalate U.S.-Iran tensions. An expanding action-reaction dynamic between the United States and Iran has the potential to escalate into significant conflict. The United States military has the capability to undertake a large range of options against Iran in the event of conflict, both against Iran directly and against its regional allies and proxies. However, Iran's alliances with and armed support for armed factions throughout the region, and its network of agents in Europe, Latin America, and elsewhere, give Iran the potential to expand confrontation into areas where U.S. response options might be limited. Members of Congress have received additional information from the Administration about the causes of the uptick in U.S.Iran tensions and Administration planning for further U.S. responses. They have responded in a number of ways; some Members have sought to pass legislation requiring congressional approval for any decision by the President to take military action against Iran.