Washington: Pressed this week to define President Donald Trump’s goals in escalating military and economic pressure on Iran, one of his top foreign policy aides ticked through a familiar list: End the country’s support for terrorism, stop its missile launches and then, most importantly, keep Iran more than a year away from the capability to build a nuclear weapon.

The United States would insist on “zero enrichment for Iran,” Brian H. Hook, the State Department’s special envoy for Iran, told a small group of reporters. That would assure Tehran could produce no new nuclear material, and thus never get closer to building a weapon than it is now.

It was a telling moment in a strange, circular week of mutual threats and missed signals between bitter adversaries. Designing an agreement that would assure it would take Iran a year or more to “break out” and become a nuclear power - giving the United States, Israel and others plenty of time to respond - was the driving force behind the 2015 nuclear deal that was negotiated under former President Barack Obama.

Every requirement, every concession in the deal, was measured against how it would affect that timeline. And by all accounts, that deal was working before Trump withdrew the United States from it in May 2018, calling it a “disaster.”

While Trump has insisted that he could confront Iran without leading to a military conflict, other officials in his administration have, effectively, set a red line that they said Tehran would cross at its peril.

“We are restoring deterrence while working toward a new and better deal,” Hook said. “We lost deterrence under the Iran deal.”

Officials have not specified what kind of reaction - military or otherwise - would be ordered if Iran built up enough of a stockpile of uranium and took other steps that would cross that threshold. But they have acknowledged that if President Hassan Rouhani of Iran goes ahead with plans announced last week, it would, eventually, give Iran that capability.

Rouhani said Iran should no longer be restricted by the terms of a deal that Trump had already violated by reimposing sanctions. He said he would gradually end the limits on nuclear fuel production that Iran has been observing since 2015.

The Trump administration’s newest declaration illustrated the confusion swirling around Congress, America’s allies and its adversaries as they press the White House about the president’s real strategic goals. Is this a confrontation about forever ending Iran’s nuclear ambitions? Ending its missile programme? Stopping its support of terrorists? Or creating the conditions for the Iranian people to overthrow their clerical government?

The answers given by Secretary of State Mike Pompeo suggest all of the above, as well as the creation of an Iran that is “a normal country,” as he has put it. But, so far, Trump’s top aides have had enormous difficulty prioritising their goals, or explaining how they turn a confrontation into a negotiation.

That may be the result of a president who knew what he didn’t like - a deal negotiated under Obama, in which key restrictions on nuclear fuel production expire starting in 2030 - before determining how he wanted to replace it.

“They were so committed to leaving the deal, because it had been negotiated by the Obama administration, that they did it without thinking through the predictable consequences,” said Vipin Narang, an associate professor at the Massachusetts Institute of Technology who tracks nuclear proliferation issues.

It is possible that Trump is just staging a confrontation to force Iran to negotiate a new deal. This week, he said he wanted to talk to Rouhani. But the initial reaction from Iran was underwhelming.

Rewriting the nuclear deal would bear some resemblance to what Trump did when he tossed aside the North American Free Trade Agreement, only to emerge with a new one, negotiated with Canada and Mexico, that bears a considerable resemblance to its predecessor. On that issue, Trump was in his comfort zone: Rebalancing the scales in trade in goods is what animates him most.

But nuclear strategy operates by different rules. As Trump has learned with North Korea, even the prospect of building glistening hotels on pristine beaches is not enough to make authoritarian leaders give up the technology that can keep them from being overthrown by outside powers.