The U.S. Has Turned Up Pressure on Iran. See the Timeline of Events.


WASHINGTON — The attacks on two tankers in the Gulf of Oman on Thursday have again sent the United States and Iran, two longtime adversaries, hurtling toward potential crisis. The challenges are diplomatic and economic, as well as military.

But that course was set a year ago, foreign policy experts say, when President Trump, enforcing his “maximum pressure” campaign against Tehran, withdrew the United States from an Obama-era agreement meant to rein in Iran’s nuclear ambitions. Tehran did not immediately retaliate in the months after, but as increased American pressure and sanctions have put a strangle on its economy, Iran may now be hitting back.

“Iran was getting repeatedly punched in the face by the Trump administration, and they’ve been warning for months there will be consequences,” said Karim Sadjadpour, an Iran expert at the Carnegie Endowment for International Peace. “The Iranian economy has long been riddled by endemic mismanagement, corruption, cronyism, and brain drain. Sanctions makes all these problems worse.”

Here’s a look at how the United States turned up the pressure on Iran.

President Hassan Rouhani of Iran said that his country would continue to abide by the terms of the deal. He criticized Mr. Trump for pulling out of the pact as well as other international treaties.

Mr. Trump, over the objections of Pentagon officials, announced that he was designating a powerful arm of the Iranian military, its Islamic Revolutionary Guards Corps, as a foreign terrorist organization.

It was the first time that the United States named part of another country’s government as that type of official threat. The designation imposed wide-ranging economic and travel sanctions on the group, which carries out operations across the Middle East, trains Arab Shiite militias and oversee businesses in Iran. The sanctions also applied to organizations, companies and individuals with ties to the Revolutionary Guards.

The designation, which went into effect April 15, “will significantly expand the scope and scale of our maximum pressure on the Iranian regime,” Mr. Trump said in a statement.

Gen. Joseph F. Dunford, the chairman of the Joint Chiefs of Staff, opposed the move, arguing that it would allow Iranian leaders to justify operations against Americans overseas, especially Special Operations units and paramilitary units working under the C.I.A. But Secretary of State Mike Pompeo and John R. Bolton, the national security adviser, pushed for it.

Iran’s Supreme National Security Council said it was designating as a terrorist organization the United States Central Command, which oversees American military operations in the Middle East.

American officials said they began seeing stepped-up threats against their forces in the region, as well as reports that Iranian-backed Shiite militias were considering attacks on American troops in Iraq.

Meanwhile, Iran’s oil exports fell by more than half since Mr. Trump announced he was pulling out of the nuclear deal, to under one million barrels a day.

Crude oil prices rose more than 3 percent, indirectly bolstering Iran’s revenue as an oil producer.