On Feb. 18, as President Trump weighed whether to launch military attacks on Iran, Chris Wright, the energy secretary, told an interviewer he was not concerned that the looming war might disrupt oil supplies in the Middle East and wreak havoc in energy markets.

Even during the Israeli and U.S. strikes against Iran last June, Mr. Wright said, there had been little disruption in the markets. “Oil prices blipped up and then went back down,” he said. Some of Mr. Trump’s other advisers shared similar views in private, dismissing warnings that — the second time around — Iran might wage economic warfare by closing shipping lanes carrying roughly 20 percent of the world’s oil supply.

The extent of that miscalculation was laid bare in recent days, as Iran threatened to fire at commercial oil tankers transiting the Strait of Hormuz, the strategic choke point through which all ships must pass on their way out of the Persian Gulf. In response to the Iranian threats, commercial shipping has come to a standstill in the Gulf, oil prices have spiked, and the Trump administration has scrambled to find ways to tamp down an economic crisis that has triggered higher gasoline prices for Americans.

The episode is emblematic of how much Mr. Trump and his advisers misjudged how Iran would respond to a conflict that the government in Tehran sees as an existential threat. Iran has responded far more aggressively than it did during last June’s 12-day war, firing barrages of missiles and drones at U.S. military bases, cities in Arab nations across the Middle East, and on Israeli population centers.

U.S. officials have had to adjust plans on the fly, from hastily ordering the evacuation of embassies to developing policy proposals to reduce gas prices.

After Trump administration officials gave a closed-door briefing to lawmakers on Tuesday, Senator Christopher S. Murphy, Democrat of Connecticut, said on social media that the administration had no plan for the Strait of Hormuz and did “not know how to get it safely back open.”

Inside the administration, some officials are growing pessimistic about the lack of a clear strategy to finish the war. But they have been careful not to express that directly to the president, who has repeatedly declared that the military operation is a complete success.

Mr. Trump has laid out maximalist goals like insisting that Iran name a leader who will submit to him, while Secretary of State Marco Rubio and Defense Secretary Pete Hegseth have described narrower and more tactical objectives that could provide an off-ramp in the near term.

Karoline Leavitt, the White House press secretary, said the administration “had a strong game plan” before the war broke out, and vowed that oil prices would drop after it ended.

“The purposeful disruption in the oil market by the Iranian regime is short term, and necessary for the long-term gain of wiping out these terrorists and the threat they pose to America and the world,” she said in a statement.

This article is based on interviews with a dozen U.S. officials, who asked for anonymity to discuss private conversations.

‘Show Some Guts’ Mr. Hegseth acknowledged on Tuesday that Iran’s ferocious response against its neighbors caught the Pentagon somewhat off guard. But he insisted that Iran’s actions were backfiring.

“I can’t say that we anticipated necessarily that’s exactly how they would react, but we knew it was a possibility,” Mr. Hegseth said at a Pentagon news conference. “I think it was a demonstration of the desperation of the regime.”

Mr. Trump has displayed growing frustration over how the war is disrupting the oil supply, telling Fox News that oil tanker crews should “show some guts” and sail through the Strait of Hormuz.

Some military advisers did warn before the war that Iran could launch an aggressive campaign in response, and would view the U.S.-Israeli attack as a threat to its existence. But other advisers remained confident that killing Iran’s senior leadership would lead to more pragmatic leaders taking over who might bring an end to the war.

When Mr. Trump was briefed about risks that oil prices could rise in the event of war, he acknowledged the possibility but downplayed it as a short-term concern that should not overshadow the mission to decapitate the Iranian regime. He directed Mr. Wright and Treasury Secretary Scott Bessent to work on developing options for a potential spike in prices.

But the president did not speak publicly about these options — including political risk insurance backed by the U.S. government, and the potential of U.S. Navy escorts — until more than 48 hours after the conflict started. The escorts have not yet taken place.

Mr. Wright, the energy secretary, caused a market commotion Tuesday when he posted on social media that the Navy had successfully escorted an oil tanker through the Strait of Hormuz. His post drove up stocks and reassured oil markets. Then, when he deleted the post after administration officials said no escorts had taken place, markets were once again thrust into turmoil.

Efforts to resume shipments have been complicated by intelligence that Iran was preparing to lay mines in the strait, one U.S. official said. The Iranian operation was only in its earliest stages, but the preparatory efforts spooked the Trump administration. The U.S. military said on Tuesday evening that its forces had attacked 16 Iranian mine-laying vessels near the strait.

As the conflict has roiled global markets, Republicans in Washington have grown concerned about rising oil prices damaging their efforts to sell an economic agenda to voters ahead of the midterm elections.

Mr. Trump, both publicly and privately, has been arguing that Venezuelan oil could help solve any shocks coming from the Iran war. The administration announced on Tuesday a new refinery in Texas that officials said could help increase oil supply, ensuring that Iran does not cause any long-term damage to oil markets.

A Potential Off-Ramp The confidence that White House officials had that the shipping lanes could stay open is surprising given that Mr. Trump authorized a military campaign last year against the Houthis, a Yemeni group backed by Iran, that had used missile and drone attacks to bring maritime commerce in the Red Sea to a halt.

In a social media post last March announcing he had authorized military strikes against the Houthis, Mr. Trump said that the attacks had cost the global economy billions of dollars, and that “no terrorist force will stop American commercial and naval vessels from freely sailing the Waterways of the World.”

But since the start of the war in Iran, Mr. Trump has not offered a consistent message. In private, his aides have said they feel frustration over his lack of discipline in communicating the objectives of the military campaign to the public.

Mr. Trump has said both that the war could go on for more than a month and that it was “very complete, pretty much.” He also said the United States would “go forward more determined than ever.”

Mr. Rubio and Mr. Hegseth, however, appear to have coordinated their messaging for now on three discrete goals that they began laying out in public remarks on Monday and Tuesday.

“The goals of this mission are clear,” Mr. Rubio said at a State Department event on Monday before Mr. Trump held his own news conference. “It is to destroy the ability of this regime to launch missiles, both by destroying their missiles and their launchers; destroy the factories that make these missiles; and destroy their navy.”

The State Department even laid out the three goals in bullet-point fashion, and highlighted a video clip of Mr. Rubio stating them on an official social media account.

The presentation by Mr. Rubio, who is also the White House national security adviser, appeared to be setting the stage for the president to bring an end to the war sooner rather than later. In his news conference, Mr. Trump boasted of how the U.S. military had already destroyed Iran’s ballistic missile capability and its navy. But he also warned of even more aggressive action if Iranian leaders tried to cut off the world’s energy supply.

Matthew Pottinger, who was a deputy national security adviser in the first Trump administration, said in an interview that Mr. Trump had indicated he could decide to pursue ambitious war goals that would take weeks at least.

“In his press conference, I could hear him circling back to a rationale for fighting a bit longer given that the regime is still signaling it won’t be deterred and is still trying to control the Strait of Hormuz,” said Mr. Pottinger, now the chair of the China program at the Foundation for Defense of Democracies, a group that advocates a close U.S. partnership with Israel and confrontation with Iran.

“He doesn’t want to have to fight a ‘sequel’ war,” Mr. Pottinger added.

The search for pathways out of the war has gained urgency since the weekend, as global oil prices surge and as the United States burns through costly munitions. Pentagon officials said in recent closed-door briefings on Capitol Hill that the military used up