Logistics specialists prepare to attach cargo to an MH-60S Sea Hawk helicopter on the flight deck of the Nimitz-class aircraft carrier USS Abraham Lincoln in the Persian Gulf. The aircraft carrier strike group is being deployed to the Persian Gulf to counter an alleged but still-unspecified threat from Iran. (Amber Smalley/U.S. Navy via AP)

With the USS Abraham Lincoln Carrier Strike Group dispatched to the Persian Gulf and a possible confrontation with Iran, it is worth reflecting how we got here [“U.S. cites Iran in bolstering forces in the Middle East,” Politics & the Nation, May 6]. In 2015, President Barack Obama signed the Joint Comprehensive Plan of Action (JCPOA) to ensure that Iran’s nuclear program would be exclusively peaceful. This arrangement was far from perfect, but it was a starting point and might have led to negotiations on missiles and other subjects, including Iranian support of Hezbollah and its presence in Syria. But President Trump walked away from the JCPOA a year ago.

In November, the United States unilaterally imposed sanctions and listed conditions that Iran had to meet before new negotiations could begin. We allowed eight countries to phase out their purchase of Iranian oil but have canceled those waivers. There is a promise of more sanctions. We have listed the Iranian Revolutionary Guard Corps as a terrorist organization, in addition to a number of Iranian entities and individuals. Not surprisingly, Iran has listed some American organizations in Iraq as terrorists. This increases the danger of a confrontation that could turn into war.

If the proximate cause of war with Iran can be blamed on some action the Islamic republic takes against us, the responsibility for the war will be ours.

Thomas Greene, Bethesda