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Yemen's Houthi militia continues to launch drones and missiles at ships in the Red Sea six weeks after the US and UK launched an air campaign to stop such attacks, testing Washington's commitment to ending the rebel group's threat in an important global trade route.
The attacks are part of a regional escalation that followed Hamas' October 7 surprise attack into southern Israel, killing around 1,200 people, and Israel's retaliatory bombardment and ground invasion of Gaza that has killed more than 29,500 people.
President Joe Biden's administration has tried to balance a strong military response to the attempted Red Sea blockade by the Iran-backed Houthis with the need to avoid the US becoming embroiled in another Middle East war or antagonising Iran, analysts say.
At the same time, the cost of its Red Sea operations is mounting rapidly and detracting from Washington's longer term focus of countering China in the Pacific region.
Six weeks ago, the US and UK launched an air campaign targeting Houthi weapon stores and launch sites to stop Houthi missile and drone attacks on shipping in the Red Sea – which carries around 12 per cent of global trade.
Around 10 other countries in a wider coalition, including Australia, Denmark and Bahrain, provided varying degrees of support for the strikes.
Several rounds of bombardment and missile strikes followed the initial strikes on January 11, but the attacks on shipping continue.
On Tuesday, the EU launched a naval task force comprising France, Germany, Italy, and Belgium, to defend ships from attacks. This is in parallel with a US-led multinational task force, Operation Prosperity Guardian, that began patrolling waters off Yemen in December.
The Houthis claim they are attacking ships linked to Israel, in an attempt to end the Gaza war through economic pressure, although many of the vessels hit have had no link to Israel or the US.
former US deputy assistant secretary of defence for the Middle East
Short of a declaration of war, the US and European allies have been hesitant to carry out sustained strikes on the Houthis, with the Pentagon insisting the US is “not at war” with the group.
“In general, the Biden administration has been relatively cautious in terms of its use of force, and we’ve seen this both in the Middle East, and as well as in Ukraine,” says Raphael Cohen, an air power strategist at the Rand US defence think tank.
“So, I don’t think the Biden administration will ratchet up military pressure unless something – or some event – truly forces their hand, like what happened with the Tower 22 incident several weeks back,”
The attack on Tower 22 military outpost in Jordan, which killed three American soldiers, triggered the most forceful US retaliation against Iran-backed militias in Iraq who have escalated their attacks on American forces in the regions since the Gaza war began.
Global inflation risk
Despite Mr Biden’s hesitancy in Yemen, there is an urgency to the campaign: the volume of trade between the shortest and most cost-effective shipping route between Asia and Europe has plummeted since the attacks began.
Egypt, already in an economic crisis, has reported a 50 per cent drop in revenue from ships transiting between the Red Sea and Mediterranean via its Suez Canal as shipping companies opt to send their vessels around the Africa's Cape of Good Hope.
Globally, the attacks have pushed up inflation as shippers incur higher fuel costs from taking the longer route, and from higher insurance premiums for ships risking the Red Sea route.
Economically fragile countries and communities are now under more pressure, paying more for fuel and basic goods, while high-value supply chains have also been disrupted.
The military deployment to defend against and deter the attacks also carries a rising price tag, with much of the burden borne by the US.
US defence costs
At the end of January, the Pentagon said the cost of the deployment over four months was $1.6 billion – with two aircraft carriers rotating into the region after the start of the Gaza war.
But this does not include missile interceptions. It was revealed last week the US had fired 100 missiles from its Standard Missile systems to shoot down Houthi missiles, each costing anywhere from $4 million to $6 million.
The missiles are in high demand: Raytheon, a US defence firm, makes around 100 SM-6 missiles a year – the most advanced variant – and is slowly ramping up production to 300 a year by the mid-2020s, as the US eyes a naval standoff with China in the Pacific.
While a combined $2 billion cost over four months might seem small compared with a defence budget of around $900 billion, the US might also send up to $17 billion to Israel this year, much of it military aid.
That is in addition to recent security commitments to US allies Taiwan and Ukraine.
All these pledges to US allies are dependent on a Senate vote that is expected soon.
Rising Middle East security costs are now more than the $15.4 billion the US Indo-Pacific Command requested in 2024 for projects to counter the Chinese military, which has long been a strategic priority of US presidents following the wars in Iraq and Afghanistan.
Meanwhile, the US Navy's super carriers, the backbone of its global military operations, are in short supply. America has 11 of these nuclear-powered, 100,000 tonne-plus vessels but typically keeps only three or four at sea at a given time.
Three are currently in the Pacific – the USS Ronald Reagan, USS Carl Vinson and the USS Theodore Roosevelt – having taken part in military exercises with Japan, while the USS Dwight D Eisenhower is in the Red Sea.
“I think the challenge the Biden administration finds itself in is twofold – part military and part political,” Mr Cohen says.
“On the military end, we can devote more assets to the Houthis, but we don’t want to redirect assets from both Europe and the Indo-Pacific at the same time. On the political end, the Biden administration really does not want to see itself embroiled in yet another Middle Eastern war, particularly now that we are heading into an election year.”
Operating the Dwight D Eisenhower, as well as its supporting ships in the carrier group, costs anywhere between $6 million and $8 million a day – between $2 billion and $3 billion per year.
But experts say the US might need to send reinforcements just to protect its current deployment in the Red Sea, after a near missile strike on a US naval ship in January.
“I think the US is in a very difficult position. On the one hand we surged military assets to the region to try to deter an expansion of the conflict, on the other it may have antagonised Iran and of course provided more targets,” says Michael Patrick Mulroy, former deputy assistant secretary of defence for the Middle East.
“We have also been measured in our responses to near non-stop attacks on our forces in an attempt not to escalate the current situation but that may have just emboldened Iran and their proxy forces as they do not fear the consequences,” he says.
Last week, it was revealed that the Houthis had attempted to use a submarine drone that some experts suspect had been supplied by Iran, like much of the Houthis' military hardware, according to UN and US assessments.
“I think the US has to make it clear that we will increase our level of response with every attack, and if any of those attacks are successful, Iran should know that they will be held directly responsible,” Mr Patrick Mulroy says.
“That means eventually targets in Iran must be on the table. Iran has no problem fighting until the last proxy force. That is why they have them. They need to have real consequences.”
