Donald Trump, the president who returned to the White House in January promising to be a “peacemaker”, has taken a dramatic step to insert the US into the fraught conflict between Iran and Israel.

Far from bringing peace to the Middle East since taking office, Trump is now presiding over a region on the precipice of even greater warfare – a fight in which America is an active participant.

In a televised address to the nation from the White House just over two hours after announcing on social media that American forces had struck three nuclear sites in Iran, the American president said the operation had been a “spectacular success”.

He expressed hope that his move would open the door to a more lasting peace where Iran no longer had the potential to become a nuclear power.

Iran has said that there was only minor damage to its heavily fortified Fordo nuclear site. Time will tell which side is correct.

Flanked by Vice-President JD Vance, Secretary of State Marco Rubio and Defence Secretary Pete Hegseth, Trump warned Iran that if they did not abandon their nuclear programme, they would face future attacks that were “far worse and a lot easier”.

There were “many targets left”, Trump said, and the US would go after them with “speed, precision and skill”.

Despite the president’s bravado, a continued American military engagement in Iran may be a worst-case scenario for the US, the region and the world.

UN Secretary General António Guterres warned of a “spiral of chaos” that could result from the American decision to escalate the conflict, noting that the Middle East was already “on edge”.

If Iran retaliates – as Ayatollah Ali Khamenei warned would happen in the event of a US attack – then the American side may feel compelled to respond.

Trump’s rhetoric earlier this week that Iran had to “unconditionally surrender” had put the president in a position where it would be difficult for him to back down. Iran, with its own threats, had backed itself into a similar corner.

This is how wars start – and how they can expand beyond the control, and imaginations, of those involved.

On Thursday, Donald Trump gave the Iranians a two-week deadline but that turned out to be much shorter than expected – just two days. On Saturday night, the US president announced he had acted.

Was the two weeks for negotiations a feint? A bid to lure the Iranians into a false sense of security this weekend? Or did behind-the-scenes negotiations led by Trump’s designated peacemaker Steve Witkoff collapse?

In the immediate aftermath of the strikes, little is known. But in his social media post and in his televised address, Trump tried to open the door for peace.

That may be an optimistic outlook, however. While the Israelis have made considerable efforts toward degrading Iran’s military capabilities, the ayatollah still has weapons at his disposal.

Things could get messy fast.

Now the waiting game begins. How will Iran respond to attacks on three of its sites, including Fordo, seen as the crown jewel of its nuclear programme?

Trump appears to be hoping the US strikes force Iran to make greater concessions at the negotiating table, but it seems unlikely that a nation unwilling to talk while under Israeli attack will be more inclined when American bombs are also falling.

And while Trump seemed to be implying that the US attack was a singular, successful event, if that’s not the case, then the pressure to strike again will grow – or the president will have taken a serious political risk for minimal military gain.

That risk includes domestic political concerns, along with questions of international security.

The prospect of a US attack on Iran had already prompted sharp criticisms not only from Democrats but also from within Trump’s own “America First” movement.

The president’s unusual decision to give his national address flanked by three of his closer advisors may have been an attempt to project unity within his party.

Vance, in particular, has been an outspoken advocate of a more restrained American foreign policy and, recently, had taken to social media to make the case that Trump is still a non-interventionist who should be given the benefit of the doubt by his supporters.

If this attack is a one-off event, Trump may be able to smooth over the divisions within his base. But if it pulls the US into a larger conflict, the president could have an uprising with his ranks.

Saturday’s attack was an aggressive move for a president who boasted of starting no new wars during his first presidential term and who regularly railed against predecessors who had drawn the country into foreign conflicts on the campaign trail last year.

Trump has made his move. Where it goes from here is not entirely within his control.

Follow the twists and turns of Trump’s second term with North America correspondent Anthony Zurcher’s weekly US Politics Unspun newsletter. Readers in the UK can sign up here. Those outside the UK can sign up here.