As anticipated, the United States last week reimposed trade sanctions with Iran. Sanctions were suspended by the 2015 international agreement reached with the government of Iran that capped its nuclear program. U.S. President Donald Trump has been unyielding in his hostility to that deal, and withdrew his country from it earlier this year. He hopes that renewed pressure on Iran — and its trade partners — will force Tehran to change its behavior. That is an overly simplistic — and optimistic — assessment. Instead, the move will likely deepen rifts between Washington and its allies, and give Iran, which had been abiding by the deal, reason to abandon it.

The Joint Comprehensive Plan of Action (JCPOA) was widely agreed to have succeeded in halting Iran's progress toward the development of a nuclear weapons capability. Trump, however, believed that the deal was flawed on several counts. It capped, rather than permanently curtailed, Tehran's ability to acquire a weapon, and it did not address other forms of Iranian misbehavior, such as support for proxies elsewhere in the region.

All other parties to the agreement, including the International Atomic Energy Agency, which was responsible for assessing Iranian compliance, agreed that "the JCPOA is working and delivering on its goal, namely to ensure that the Iranian program remains exclusively peaceful," as a statement from European signatories noted. And while the deal did not tackle the thorny issue of Iran's disruptive behavior, it was not for lack of trying. Negotiators labored for nearly two years on an agreement and Iran absolutely refused to extend the scope of the agreement beyond nuclear issues. The agreement was not perfect, but it was good enough to win the support of all involved.