If Iran did attack two tankers in the Gulf of Oman this week, as President Donald Trump claims, he’s doing a lousy job of making that case to the rest of the world.

The sad fact is he has to make a case because, in his 2½ years in office, he has told so many lies and alienated so many allies. If he decided to respond to the attacks with new economic pressure or military action, he would need the support of those allies, and to earn that support, he would need to present extraordinarily persuasive evidence of Iran’s culpability.

He has not yet produced that evidence. It was an egregious mistake to let Secretary of State Mike Pompeo make the initial accusation against Iran. First, Pompeo is on record as supporting regime change in Tehran; for him to come forth—instead of a more relevant figure, such as the secretary of defense or the director of national intelligence—infuses the charge with bias.

Second, the language Pompeo used was less than compelling. “It is the assessment by the United States government that the Islamic Republic of Iran is responsible for the attacks,” he said on Thursday. “The assessment is based on intelligence, the weapons used, the level of expertise needed to execute the operation, recent similar Iranian attacks on shipping, and the fact that no proxy group operating in the area has the sources and proficiency to act with such a high degree of sophistication.”

Among several things missing here is the level of confidence in the assessment. The omission is unusual and possibly, for that reason, telling. When U.S. intelligence agencies first analyzed the theft of emails from the Democratic National Committee in the spring of 2016, for example, they concluded with “high confidence” that Russia was the culprit. When chemical weapons were fired in Syria in April 2017, Trump’s secretary of state at the time, Rex Tillerson, said U.S. intelligence had “a very high level of confidence” that the weapon used was sarin nerve gas and that the attack was ordered by Bashar al-Assad’s regime. Then–Secretary of Defense James Mattis said that he’d personally reviewed the intelligence and had “no doubt” that the Syrian regime was responsible.

On Friday, the Pentagon released fuzzy video footage of sailors on a small boat removing an object from the side of a ship. Officials said that the small boat belonged to the Iranian Revolutionary Guard Corps, the object was an unexploded mine, and the ship was one of the two tankers that were attacked. Maybe. We all await footage showing sailors from a similar boat placing a mine on the side of a tanker. The picture is further muddied by the fact that the Japanese owner of one of the tankers has since claimed that the hole in his ship was well above the water—beyond the reach of someone in a small boat.*

It is also, at the very least, strange that the attack on the Japanese tanker came as Iran’s supreme leader, Ayatollah Ali Khamenei, was meeting with Japan’s prime minister, Shinzo Abe. I asked several specialists in Iranian politics Friday morning if it was possible for the Revolutionary Guard, or some Iranian rogue faction, to have launched such an attack on its own, without the approval or knowledge of the supreme leader or President Hassan Rouhani. They all said they could imagine the guard acting independently of Rouhani—but never in defiance of the supreme leader.

Would Khamenei have met with Abe, in what was described as a peace-seeking session, knowing that one of his military units was about to attack a tanker flying a Japanese flag? Very doubtful. If he’d wanted to snub Abe, he could have simply refused the meeting. (He has, as a matter of policy, never met with any U.S. official.)

So here are some possibilities:

• The attack was mounted by the IRGC, or some faction of the IRGC, with Khamenei’s consent or with some sort of nod that its leaders interpreted as his consent. (Maybe he didn’t know they’d attack a Japanese vessel; maybe they didn’t know he would be meeting with the Japanese prime minister; maybe they didn’t know the tanker was Japanese-owned.)

• It was mounted by some Iranian-backed militia, from elsewhere in the region, acting on its own but in a way that its leaders thought would please their masters.

• It was launched by Saudi Arabia or the United Arab Emirates in a way to make it look like Iran was at fault.

These theories (and that’s all they are, at this point) suggest that the attack was launched to provoke an American overreaction, which might trigger a war. Or, if Khamenei knew the attacks were coming, he might have condoned them as a preemptive measure, a warning to the United States—which he believes is preparing for war—that Iran will counter its aggression. (Rouhani has previously warned that Iran could respond to U.S. military action by closing the Strait of Hormuz, a narrow but major waterway for global oil traffic.)

The fact is the Iranians have cause for worry. Trump’s national security adviser, John Bolton, has long advocated regime change in Tehran, by force if necessary. Trump himself, of course, pulled out of the Iran nuclear deal, reimposed sanctions on Iran, and took the extra, unusual step of imposing “secondary sanctions” on all other countries that continued to do business with Iran—which Iran could sensibly see as an act of economic warfare.

Earlier this year, when Pompeo considered tagging the IRGC as a “foreign terrorist organization,” senior U.S. military officers argued against the move on the grounds that it might open U.S. forces in the region to violent action by Iran. Pompeo took the step, despite this opposition; the Iranians haven’t yet attacked U.S. forces (or anything belonging to the United States), but, if they did attack the tankers, it might be a prelude to more—just as the officers predicted.

On Friday, in a statement about the tanker attacks, a spokesman for Central Command—which oversees all U.S. military operations in the Middle East and South Asia—emphasized, “We have no interest in engaging in a new conflict in the Middle East. We will defend our interests, but a war with Iran is not in our strategic interest, nor in the best interest of the international community.”

The question is what Trump thinks and to what extent he’s prone to resist, or fall prey to, the pressures of escalation brought on by these attacks and the ensuing tensions.

The region has seen tanker wars in the past, most notably from 1984–87, when more than 300 oil tankers were attacked in the Persian Gulf. That war was but one battle zone in a wider, extremely destructive eight-year war between Iraq and Iran. This early phase of what might be a new tanker war grew out of capricious decisions, notably Trump’s withdrawal from the Iran nuclear deal, which he took for no reason at all, other than his hostility toward President Barack Obama, who negotiated it, and Trump’s cuddling up to the Saudi royal family and Israeli Prime Minister Benjamin Netanyahu, both of whom, as one former U.S. official put it, are willing “to fight Iran to the last ounce of American blood.”

Trump has said he doesn’t want war with Iran. He recently told reporters he wanted the Iranian leaders to call him; he even gave his phone number to Swiss officials, who have served as an intermediary between Washington and Tehran in past eras of tension. When Abe saw Khamenei in Iran, he handed him a letter from Trump. (Khamenei told Abe he had no interest in any message from the current occupant of the White House.)

Who knows what will happen next? We don’t really know what happened this week. The people around Trump are pushing for punishment and retaliation. Such pressures can unleash a logic of escalation, unless someone steps in to stop it. This isn’t the most hopeful thing to say, but that someone probably has to be Trump.

Correction, June 14, 2019: This piece originally misstated that the owner of one of the ships concluded it was attacked by a torpedo. The conclusion was that it was not a torpedo.