The Trump administration’s sanctioning of Iranian Foreign Minister Mohammad Javad Zarif left critics, and even some supporters, of the president’s Iran policy scratching their heads about what it achieved, though it did appear to unite Iran’s own often-fractious leadership.

Iranian President Hassan Rouhani on Thursday called the move “childish” and said it was a contradiction of President Trump’s claims to be seeking dialogue with Tehran. The Revolutionary Guard Corps, more often seen to be undermining Rouhani, called it “ridiculous” and “illegal,” while Iran’s official armed forces labeled it “undiplomatic and forlorn.”

At home, the action underscored ongoing confusion about the end goal of the administration’s “maximum pressure” campaign against Iran and how it proposes to get there.

Sanctions have cut Iranian oil exports — the country’s principal moneymaker — to a bare minimum, and “they cannot sustain this,” said a senior administration official.

“The fact that we are not rushing to offer them concessions . . . comes as something of a surprise” to the Iranians, said the official, who spoke on the condition of anonymity under rules set by the administration.

The objective is to “get them to change their behavior, to do what is only in their best interests.” If that cannot happen, the official said, “we can reduce their ability” to achieve their own policy goals.

But the scope of U.S. demands remains unclear, along with what Iranian actions would be enough to cause any easing of punitive administration measures.

Trump has said repeatedly that he would talk to Iran’s leadership without preconditions. At various times, he has said his only demand is that “they can’t have a nuclear weapon.”

He has indicated he wants to renegotiate the international nuclear deal, designed to prevent Iranian weapons activity, which he withdrew the United States from last year.

Secretary of State Mike Pompeo and Trump’s national security adviser John Bolton have sent somewhat different messages, demanding that, in addition, Iran end its ballistic-missile program, withdraw all troops and military advisers from beyond its borders and cease support for groups the administration deems terrorist organizations.

Iranian leaders have publicly refused dialogue unless sanctions are lifted.

It was unclear how sanctioning Zarif contributed to U.S. goals. The proximate reason appeared to be the administration’s irritation over his multiple media encounters, including television interviews, during a visit to the United Nations in New York last month. Zarif’s “spewing of propaganda” and his defense of policies the administration finds “particularly egregious” was unacceptable, the senior official said.

His “exploitation of our diplomatic courtesies” in allowing him a limited visa to come to New York in the first place was “an insult,” the official said.

“This decision appears to have been driven by a personal antipathy toward Zarif,” said Karim Sadjadpour of the Carnegie Endowment for International Peace. “What makes Zarif effective is his persuasive powers with Western media and analysts, as well as European and Asian officials,” although “it’s not clear how sanctioning him reduces this effectiveness.”

In a Thursday morning interview with Fox News, Bolton continued the personal attacks. The U.S.-educated Zarif, he said, “is not a diplomat. He’s a con man. He’s a shill. He’s a grifter. This is the sort of step by the United States that shows he’s illegitimate.”

Although Trump said last month that he had instructed Treasury Secretary Steven Mnuchin to sanction Zarif, under an executive order he issued sanctioning Ayatollah Ali Khamenei, Iran’s supreme leader, a decision on Zarif was postponed to allow space for diplomacy, according to the administration.

French President Emmanuel Macron and Japanese Prime Minister Shinzo Abe have both offered to mediate. Qatar and Oman, two Persian Gulf countries that retain cordial relations with Iran, have indicated a willingness to serve as intermediaries, though there is little sign that substantive exchanges have taken place.

Sen. Rand Paul (R-Ky.) won Trump’s blessing to meet with Zarif while the foreign minister was in New York. “The answer is ‘yes,’ ” Trump told reporters after a conversation with Paul, “and if the other senators ask me to get involved, I’d probably say ‘yes,’ depending on who they were. I have many people involved, and Iran is going to work out very nicely.”

Paul has never confirmed that he met with Zarif, and when asked, Paul spokesman Sergio Gor said, “We don’t have any comment.”

The senior administration official said it was “murky” whether a meeting took place.

However, Paul was clearly displeased about the new sanctions on the foreign minister.

“If you sanction diplomats you’ll have less diplomacy,” he tweeted after the measures were announced Wednesday.

Luke Coffey, director of the Allison Center for Foreign Policy Studies at the Heritage Foundation, praised overall what he called a “deliberate” and coordinated administration policy toward Iran over the past two years.

But “then I see things like . . . the announcement of sanctions against the foreign minister,” Coffey said. “Why? I have no idea. I understand the argument . . . but I don’t understand the timing.”

Other Iranian officials may follow. “We’re just getting started,” the administration official said. Zarif is “the first to be designated under the executive order” against Khamenei. “The reality is that when you take a new action with a new authority, it takes a little bit of time to make sure that we’re getting it right.”

If Trump were involved in negotiations with Iran, as he has been with North Korean leader Kim Jong Un, the official said, he would want to go to the top. “There’s a reason why they call Ayatollah Khamenei the supreme leader. If not him . . . it would have to be someone who very clearly has his authority to make decisions.”

“As with North Korea, if we’re going to be involving the president — and I’m not saying that’s a certainty,” it would require an interlocutor who is not Khamenei’s “minister of propaganda,” the official said.

Despite declarations in Washington and Tehran that neither side wants a war, tensions have escalated this summer with Iran’s alleged mining of foreign-flagged oil tankers in the Persian Gulf, the mutual downing of U.S. and Iranian drones and the Iranian seizure of a British-owned tanker that remains under guard in the port of Bandar Abbas.

Sen. Tom Cotton (R-Ark.), an Iran hawk who supported a U.S. strike against the country after it downed an American drone, said he was confident the United States would win swiftly and easily in any military confrontation with Iran.

“Two strikes,” he said in a PBS broadcast. “The first strike and the last strike.”

Others are less certain. “While they are no match for the United States,” the Iranian military “could provide Iran with the defensive capabilities they need,” with hundreds of thousands of troops, ballistic missiles, submarines, and home turf advantage, said retired Adm. William H. McRaven, who headed the U.S. Special Operations Command during the Barack Obama administration and spoke to reporters this week to introduce a report published by the International Crisis Group on the standoff with Iran.

“The U.S. military is more sophisticated by a magnitude of ten. Having said that, no one should think that war in Iran is going to be quick and easy,” McRaven said. “Anyone who thinks we could decimate Iran with a couple of airstrikes is terribly misguided. . . . Nothing is ever quick and easy.”