Iran has named a new supreme leader, despite President Trump saying Sunday that new leaders will not survive without U.S. approval and vowing that he personally will be intimately involved with the postwar government in Tehran.

The Islamic republic’s 88-seat Assembly of Experts named Mojtaba Khamenei, a son of the previous supreme leader, Iranian state TV announced early Monday

But any successor to the late Ayatollah Ali Khamenei, who was killed more than a week ago in the first wave of U.S.-Israeli airstrikes, is “going to have to get approval from us,” Mr. Trump told ABC News on Sunday. 

“If he doesn’t get approval from us, he’s not going to last long,” he added.

The younger Mr. Khamenei, who had been considered a possible successor, has not been seen or heard from publicly since the war started.

State TV read a statement from the Assembly, a group of clerics that selects the supreme leader, saying that it was a “strong” vote for the 56-year-old Mr. Khamenei and urging the nation to unite behind him. 

Speculation is growing about a targeted introduction of U.S. troops or special operations forces to the battlefield. Senior military analysts are suggesting that the U.S. could seize oil production hubs or whatever remains of Iran’s uranium enrichment facilities.

After nine days of U.S. and Israeli bombardment, Iran’s military is a “paper tiger,” Mr. Trump said. Members of his administration echo to the press that the president has not ruled out ground force operations.

“At some point, maybe we will,” Mr. Trump said of sending in ground troops. “If we ever did that, it would be so decimated that they wouldn’t be able to fight on the ground level.”

Sen. Thom Tillis, North Carolina Republican, drew a hard line Sunday against ground operations, including any special operations forces, saying such action would require a new Authorization for the Use of Military Force from Congress.

“When you start putting boots on the ground, and those boots may need reinforcement, that starts looking like a longer-term conflict,” Mr. Tillis told CNN.

Concerns about an expanded American role in the war were underscored Sunday when U.S. officials announced the death of a seventh American service member. The service member died Saturday from injuries suffered on March 1 during the Iranian regime’s initial wave of retaliatory attacks. The soldier’s identity is being withheld until after the family is notified.

The divergence between what the Pentagon originally articulated as the administration’s goals in Iran and what could play out now is becoming a larger issue as the campaign wears on.

Destroying Iran’s ballistic missile threat, neutering its army and navy, and eliminating its military’s capacity to retaliate, the three U.S. objectives originally outlined by Defense Secretary Pete Hegseth, are mostly complete, Mr. Trump said.

Destroying Iran’s military may prove complex, though. Its broad structure, with close to 1 million troops, combines the conventional army, the Islamic Revolutionary Guard Corps (with its Quds Force) and the Basij militia, embedded throughout the country and the civilian population, much like U.S. military reserves.

Mr. Trump’s continued commentary on the Iranian leadership vacuum reframes the conflict more as a demolition of the regime than simply targeting weapons and military forces.

The Iranian death toll stands above 1,300 people. A Saturday rally on Capitol Hill highlighted the losses as hundreds of Iranian Americans opposed the use of airstrikes and bombs as the principal way to change the situation in Iran.

“True regime change will not come from airstrikes alone,” said Seena Saiedian, a volunteer with Iranian American organizations. “True regime change requires a grassroots movement within the country.”

As the Trump administration starts to deal with domestic consequences, international relationships are fraying beyond the campaign’s boundaries.

The Strait of Hormuz, which accounts for roughly 20% of the world’s petroleum liquids transportation, according to the U.S. Energy Information Administration, remains perilous. The situation has pushed crude oil above $90 a barrel with speculation that it could climb higher if the strait does not fully reopen to tanker traffic.

The oil price surge, pushing U.S. gas prices up another 47 cents per gallon, is most deeply felt by nations leagues away. India is at risk of severe inflation as the halt in Qatari liquefied natural gas exports and rising oil prices push the country toward Russia as a supplier, in direct opposition to NATO efforts to strangle Russia’s wartime economy. The Center for Strategic and International Studies said Gulf region suppliers account for nearly 56% of India’s oil imports.

President Trump said the spike in oil prices was expected, but he considered the war a “short excursion.” He said prices will come down “very fast” once the conflict in Iran is resolved.

Oil isn’t Mr. Trump’s only international issue that the war is fueling.

British Prime Minister Keir Starmer spoke with Mr. Trump on Sunday after a week of public friction.

Mr. Trump took a stab at the British leader during his meeting with German Chancellor Friedrich Merz last week. He said it is “not Churchill we’re dealing with” and that the British naval forces offered to assist in the conflict weren’t needed.

“We don’t need people who join wars after we’ve already won,” Mr. Trump said. “It would have been nice to have had them two weeks ago.”

Spain is also at odds with the Trump administration. The Spanish government refuses to support the campaign by allowing the U.S. to use its air bases, and Mr. Trump has threatened to cut off all trade with Madrid.

The tension between these allies has arisen at a critical point. NATO intercepted Iranian ballistic missiles targeting Turkey, though it has not called on all allies to join the fight under Article 5 powers.

Mr. Trump said Saturday that the end to the conflict will be achieved only with Iran’s unconditional surrender: when “they cry uncle” or there is simply “nobody around to surrender.”