Read: How to navigate the fog of war on Iran

On Twitter, Iranian Foreign Minister Javad Zarif called the explosions and their timing “suspicious,” a statement Pompeo mocked from the podium today. “Foreign Minister Zarif may think this is funny, but no one else in the world does,” he said.

The administration’s blaming of Iran, Pompeo said, is based on intelligence as well as on Iran’s capabilities and its past behavior. The Islamic republic has, in the past, relied on proxy forces and asymmetric means to coerce concessions without having to attack the United States directly. (So far, the U.S. hasn’t made any concessions.) And the crowded shipping lanes in the region, where a significant percentage of the world’s oil supply passes through, shows just how quickly a bilateral spat can turn into something much bigger. Oil prices, which jumped after the explosions, have been a particular concern for Trump.

Numerous countries stand to be affected. “You have the regional exporters, countries with tankers, and importers, not to mention those countries with insurance firms involved, to name a few,” Ariane Tabatabai, an Iran expert at the Rand Corporation, wrote in an email. “During the 1980s Tanker War, you had upward of 30 countries whose ships were hit by Iran and Iraq.”

Ali Vaez: Trump’s ‘maximum pressure’ won’t make Iran yield

But the U.S. has recently made moves to give itself options in case the attacks do turn out to be linked to Iran. In May, White House National Security Adviser John Bolton announced the deployment of a carrier strike group to the region, and the Pentagon later announced it would send 1,500 troops to the Middle East as a “force protection” measure. The U.S. already has 60,000 to 80,000 troops in the region, though the level fluctuates, plus a number of air and naval bases in the region. Iran, meanwhile, has the powerful Islamic Revolutionary Guard Corps at its disposal; proxies operating in numerous countries, including Yemen, on Saudi Arabia’s border; and the largest arsenal of ballistic missiles in the Middle East. The administration has cited intelligence saying that Iran was preparing attacks, though Democrats who have seen the intelligence have been skeptical.

There will doubtless be a partisan battle over whether the latest suspected attacks are proof that the threat was real all along, or proof that the administration’s purportedly deterrent and defensive moves could provoke a wider conflict. Defense officials, including acting Defense Secretary Patrick Shanahan, have said that the recent deployments have deterred Iranian attacks, raising the question of whether the new attacks mean that deterrence has failed.

Caught in the middle of all that are tankers, sailors, and commuters who have nothing to do with the “maximum pressure” campaign the U.S. is waging against Iran. Bolton’s initial statement left somewhat vague what precise actions would provoke a forceful U.S. response—but the administration is already punishing Iran with unprecedentedly harsh sanctions for its regional activities. “Any attack,” that statement said, “on United States interests or on those of our allies will be met with unrelenting force.”