After weeks of negotiation, House and Senate leaders agreed late Monday on new measures targeting Iranian shipping, not only of oil but also of a wide variety of other products. The House was set to vote as soon as Wednesday, while the Senate leaders — Mitch McConnell, the Republican minority leader from Kentucky, and Harry Reid, the Democratic majority leader from Nevada — also signaled that they would move the legislation forward quickly.
"The idea is to up the ante to the greatest extent possible," said Senator Ron Wyden, Democrat of Oregon. "From a foreign policy standpoint, trying to find every possible way to up the ante makes sense."
Mark Dubowitz, the executive director of the Foundation for Defense of Democracies and a supporter of tougher sanctions, said the new measures were "a major upgrade of the sanctions regime." But he noted that the goal of the sanctions is to change the political calculus of Iran's leadership, increasing pressure to the point that it agrees to resolve concerns about whether its nuclear program is peaceful, as it insists, or aimed at producing a bomb, as many experts contend.
"There's no evidence to date that the sanctions have achieved that objective," he said.
Administration officials took pains to point out the economic damage the sanctions have inflicted on Iran. European and American sanctions have driven down its oil exports by 40 percent to 50 percent, depriving Iran of $9 billion in revenue every quarter, said Robert J. Einhorn, the State Department's special adviser on nonproliferation.