The beat of war drums over Iran has been growing steadily louder in Washington since May, when Donald Trump trashed the UN-backed nuclear pact with Tehran. But the wild threats that Trump tweeted on Sunday evening in reaction to comments by Iran’s president have taken the confrontation to a new and dangerous level.

Trump’s escalation does not appear premeditated or thought through. He faced intense bipartisan criticism after last week’s inept summit with Russia’s leader, Vladimir Putin. He is under relentless pressure from the official inquiry into alleged 2016 campaign collusion with Russia. Trump may have been looking for an easy target on which to vent his pent-up frustration.

The remarks by Hassan Rouhani, Iran’s president, warning the US not to “twist the lion’s tail” provided the spark. Intentionally or not, Trump has distracted attention from his domestic troubles, at least for now.

Trump’s vow to visit consequences on Iran “the like of which few throughout history have ever suffered” recall his scary threat last year to rain “fire and fury” on North Korea. He later switched tack completely, praising Kim Jong-un, North Korea’s dictator, after meeting him in Singapore in June.

But it would be unwise to assume Trump is merely sounding off again or that his Iran sabre-rattling is just noise. Influenced by the Saudis, who are engaged in a Middle East power struggle with Iran, and by the rightwing Israeli government of Benjamin Netanyahu, which regards Iran as an existential threat, the US has been putting more pressure on Tehran since Trump took office.

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The US president’s intemperate outburst raises questions about whether he discussed a secret deal with Putin on Iran, as rumoured before the Helsinki summit. Little has been publicly disclosed about the talks. But Netanyahu, for example, has been pushing for both leaders to up the ante and force an Iranian withdrawal from Syria.

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Iran’s leaders will certainly not dismiss Trump’s words lightly. They look at the US’s reimposition of sweeping sanctions next month, its plans to impose a worldwide embargo on vital oil exports and its incitement of Iranians to rise up in revolt, and they see an alarming pattern: made-in-America regime change.

In his eagerness to pick a fight, Trump appears to have over-interpreted Rouhani’s remarks, which were not obviously provocative. “America should know that peace with Iran is the mother of all peace, and war with Iran is the mother of all wars,” Rouhani said.

That was a reference to Saddam Hussein’s famous 1991 vow to fight “the mother of all battles” against the US. But Rouhani, known as a cautious moderate, was not threatening to attack America. His comment could be read as an offer to talk. It was also a timely reminder of what happened in 2003, when the US sought forcible regime change in Iraq. Trump’s Iran war dance is resembling ever more closely the buildup to that disaster.

Potentially even more serious were remarks on Sunday by Mike Pompeo, the US secretary of state. He reiterated familiar US-Saudi-Israeli complaints that Iran was undermining regional stability and was “committed to spreading the Islamic revolution to other countries, by force if necessary”. But Pompeo went further.

He accused senior ayatollahs, including the supreme leader, Ali Khamenei, of corruption, he offered support for an anti-regime uprising, and, most surprisingly, he attacked Rouhani and his foreign minister, Javad Zarif, personally. They were “polished frontmen for the ayatollahs’ international con artistry. Their nuclear deal didn’t make them moderates,” he said.

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Pompeo’s claim that mild-mannered Rouhani and Zarif are “violent Islamic revolutionaries” starkly illustrates how deeply ignorant US officials are about Iran after nearly 40 years of estrangement. It’s true there is much high-level corruption and human rights abuses; it’s true the country is in dire economic straits. Iran’s actions in Syria are anti-democratic and destructive.

But by undercutting moderate leaders who offer the best hope of reform and by threatening regime change, Trump and Pompeo risk entrenching the hardline mullahs and Revolutionary Guards they most revile – and bringing closer the prospect of violent confrontation.