Is Trump's pause on attacking Iranian energy for diplomacy or an escalation?

Donald Trump's decision to pause any attack on Iranian energy plants for a further 10 days could be a pivotal moment in a conflict that has now lasted almost four weeks.

The US president's commitment to deadlines is fluid - this is his second extension of this particular threat - but he uses them nonetheless for a purpose: to send signals, to distract attention and to buy time.

Take this latest promise to hold off a threatened "obliteration" of Iran's energy infrastructure, a massive escalation that could trigger both Iranian retaliation against similar Gulf facilities and damage chances of a sustainable peace and global economic recovery.

It may be Trump wanted again to calm international markets; it has not gone unnoticed this latest pause was announced minutes after trading closed on Wall Street.

The president may hope the financial world will believe his positive noises about the prospects of a diplomatic solution.

For certainly, another 10 days buys the White House time to find a political way out of the strategic hole in which it has placed itself.

There is diplomacy taking place. Messages are being exchanged between the US and Iran via intermediaries, especially Pakistan.

Both sides may be issuing largely maximalist lists of irreconcilable demands but there is still a suggestion of a possible meeting in Pakistan.

Diplomats say expectations are low. "There is a lot of smoke and mirrors," one said. "There is scepticism that a trusted channel of communication that can bear some load will emerge." But for now the president insists talks are taking place and they are going well.

However, delaying an attack on energy infrastructure also gives the US time to prepare for that attack - and maybe more.

Remember an expeditionary force of about 2,000 US Marines is already on route to the Middle East from Japan. Several thousand US paratroopers are heading to the region from California. And the Pentagon is declining to comment on a Wall Street Journal report that another 10,000 troops could be sent.

All these forces are going to take time to assemble, time Trump has just bought himself.

But to what end? Is the president giving himself military options? Is he actually planning a ground invasion of strategic locations in Iran? Or is he trying to suggest to the Iranian leadership they had better agree a deal or face worse consequences?

"If they don't [do a deal], we're their worse nightmare," Trump said on Thursday. "We'll just keep blowing them away."

Whatever Trump intends, his pause on attacking energy infrastructure simply reinforces the status quo in the short term.

It means current attacks on military targets will go on, Iranian retaliation will continue, and the Strait of Hormuz will remain closed to most merchant traffic.

This is, of course, what Donald Trump's deadline is all about, namely the consequences of not opening that sea way. The deadline extension effectively allows Iran to maintain its restrictions on the strait for another ten days.

A war that began amid talk of regime change and demilitarising Iran has largely become more a question of who controls a narrow sound of water on which the global economy depends.