The Houthis have shattered Trump's war strategy

A lightning offensive by the Iran-aligned Houthis has put them in a position to control a crucial Middle East waterway, creating a major new problem for United States President Donald Trump as his war with Iran grinds on in its seventh month.

Widening the Middle East conflict, Houthi fighters have advanced south along Yemen's coast, increasing their ability to choke off the Bab el-Mandeb Strait —the "Gate of Tears" at the mouth of the Red Sea — giving Teheran potential leverage over both of the region's main oil-shipping corridors.

The Houthis reached the island of Perim on Friday, in the middle of the strait between Yemen and Africa.

That is bad news for Saudi Arabia, which has been shipping much of its oil from Red Sea ports since the war effectively closed the Strait of Hormuz, on the opposite side of the Arabian Peninsula.

It also comes at a difficult time for Trump, who is already grappling with record-low approval ratings and searching for a way out of the conflict. Iran remains defiant despite being hurt militarily and economically.

"Just weeks ago, Trump adopted a strategy of squeezing Iran's economy while keeping military conflict at levels too low to squeeze the American economy," said Stephen Wertheim, a senior fellow at the Carnegie Endowment for International Peace.

"The Houthis have shattered Trump's plan."

The US administration can't afford to have the Houthis close the strait, driving up energy prices and disrupting global trade.

But at the same time, entering a fight with a foe that has withstood previous attacks by Saudi Arabia and the US would be a dangerous new mission for a US military already stretched by the fighting in Iran.

A senior Trump administration official said the US is focused on national security interests such as ensuring freedom of navigation in the Red Sea "while empowering our regional partners to take the lead in managing and resolving regional security challenges".

Iran responded to US and Israeli attacks earlier this year by disrupting the Strait of Hormuz, the outlet to the Gulf through which around a fifth of global oil supplies flowed before the war.

If the Houthis close Bab el-Mandeb, that would deal another economic blow, constraining another seven per cent of global petroleum supplies and about 12 per cent of global trade.

"This was always the worst-case scenario, that the Iranians exert control not only on the Strait of Hormuz but Bab el-Mandeb, two of the leading energy choke points in the world," said David Schenker, who served as assistant secretary of state for Near East affairs during Trump's first term and is now at the Washington Institute for Near East Policy, a think tank.

Analysts and former officials say Trump now faces a choice: devote US forces and scarce air-defence munitions to pushing back the Houthis, or leave Saudi Arabia and its allies, a Yemeni government based in the south, to confront them alone.

The Houthis seized Yemen's capital 12 years ago, and a Saudi-led military intervention has failed to dislodge them since.

Taking on the Houthis would effectively end a deal Trump struck last year in which the US would stop bombing the group in exchange for a halt to strikes on Red Sea shipping. That would be likely to expose US forces to missile attacks from Yemen.

It would also be another burden for the US military.

If US Navy vessels and aircraft have to start shooting down Houthi drones and missiles, it could also worsen diminished stockpiles of US munitions and air defence interceptors.

Tim Lenderking, who served as US special envoy on Yemen under former president Joe Biden and is now a principal at law firm Squire Patton Boggs, said that with Trump signalling an unwillingness to get directly involved militarily against the Houthis, the US needs to do more to share intelligence with the Saudis for their air campaign and step up diplomatic and material support for Yemen's internationally recognised government.

"This administration came in asking the question, 'What can Yemen do for us?'" Lenderking said during a webcast sponsored by the Middle East Institute think tank in Washington.