Doha, Qatar — Late one morning in March 1999, a United States B-52 bomber took off from RAF Fairford in Gloucestershire, headed southeast. Seven more jets followed, at two-minute intervals.

It was the start of the US-led NATO bombing of Yugoslavia, a campaign in which the Fairford base served as both a pivotal launchpad for American jets and as a fuel station for fighter planes. The British base had served a similar role during the Gulf War in 1991, and would do so again during the 2003 Iraq war and in the early stages of the US-Israeli war on Iran that began on February 28, 2026.

But in October, the US pulled all 12 of its B-1 Lancer bombers from the Gloucestershire base, amid fears that they were no longer safe there from a growing Iranian threat. Days earlier, British security forces had made several arrests, and the country’s government has accused Iran of being behind a plot to target the base — a charge Tehran has denied.

RAF Fairford is not alone. Earlier this month, the US withdrew a dozen planes from another British base, RAF Mildenhall. And in July, reports said that the US had relocated many of its military assets from its bases in the Gulf that were badly hit by Iran during the war, instead moving them to bases in Jordan, while also considering a proposal to shift them to Israel.

For decades, these bases have served as the sharp edge of the US military’s ability to project power and wage wars thousands of miles from home. For close allies, whether in Europe or the Gulf, they also worked as security guarantors against other threats.

But Iran’s ability to severely damage US facilities in the Middle East during the war, and pose a threat as far as the UK, has for the first time turned these critical strategic assets into potential liabilities, both for American allies and for the US itself, say analysts.

“The US security umbrella is becoming a double-edged sword,” Simon Mabon, a professor of international politics at Lancaster University, told Al Jazeera. “When the security of US bases is called into question, it changes Washington’s calculation of their strategic benefits. It also gives European and Gulf states reason to think seriously about the bases, given that they are becoming targets.”

How the Iran war changed the bargain

Hosting American bases has long been perceived as integral to how US allies, whether in Europe, the Gulf or East Asia, deter threats that they themselves face.

Former US President Barack Obama once spoke of an “ironclad commitment” to Gulf security, while Britain regularly invokes its so-called “special relationship” with the United States. In doing so, Britain and the Gulf have long cast themselves as willing partners to a power that — at least before current President Donald Trump — presented itself as the benevolent guarantor of its allies’ security.

But a spate of recent security incidents, many linked to the war on Iran, is testing that narrative and raising questions about whose interests these commitments serve, and whether hosting American forces could be bringing danger closer to home.

US prosecutors have charged three men they describe as Iranian-backed operatives over their alleged roles in plotting nearly 20 attacks across the United States and Europe, including on RAF Fairford.

Meanwhile, in the Gulf, Iran explicitly cited the presence of US bases as justification for targeting its neighbours, bombing Qatar, the United Arab Emirates, Saudi Arabia, Bahrain and Kuwait. Iran also bombed Oman, which does not have a permanent US base; and Jordan and Iraq, beyond the Gulf, which do host major US military facilities.

A report by the Pentagon’s watchdog released in September revealed that Iranian attacks damaged and destroyed hundreds of buildings and structures at US military installations in Kuwait, Bahrain, Qatar, the UAE, Saudi Arabia, Iraq, Oman and Jordan in the first four months of the war.

At least five KC-135 aerial refuelling tankers were damaged when they were hit at the Prince Sultan airbase in Saudi Arabia. At least one of these airborne early-warning and control aircraft was damaged on the ground in a subsequent strike.

Experts say these incidents are sharpening a security dilemma for US allies in the Gulf and Europe. Hosting US forces can expose them to retaliation in a war they had no say in starting, while those same bases help defend some of those host countries from attacks, including by intercepting missiles and providing weapons transfers.

The war has disrupted flights and shipping, threatening the oil and gas exports on which much of the region depends. US President Donald Trump said on Monday that further military action against Iran was unnecessary for now. But the US naval blockade remains in place, and shipping through the Strait of Hormuz has yet to return to normal.

“While the utility of hosting foreign military bases has always involved a calculus of risk versus the assumed assurance it provides, the perception among Gulf Arab states is certainly shifting,” Mohammad Ali Shabani, a Middle East analyst, told Al Jazeera. “The vulnerability of these assets is increasingly front-of-mind for host governments, who have not sought war, yet have been drawn into it without having had any real say.”

The US calculation

Washington faces a dilemma of its own. Bases in Europe or the Middle East give it the reach to fight faraway wars, but their presence has also provided Iran with a litany of targets.

In March, an Iranian drone hit a hangar at a British base in Cyprus that the US also uses for intelligence and logistics operations. Tehran threatened Bulgaria after reports emerged that the Eastern European NATO nation had allowed the US to use its Bezmer airbase for refuelling of planes used to attack Iran. Weeks later, Bulgaria’s defence minister announced that the US air tankers had left Bezmer for good, with the country’s president declaring that the “mission is over,” bringing relief to the village that the base draws its name from.

And in the Middle East, several key bases used by US troops have been almost rendered unusable, with those in Kuwait suffering the heaviest damage, say analysts. An attack on the Port of Shuaiba killed six US service members and destroyed an army operations centre. Iranian drones and missiles damaged aviation facilities and injured personnel at Ali Al Salem airbase, while strikes on Camp Buehring damaged maintenance and refuelling facilities.

In Qatar, an Iranian strike damaged the early warning radar system at Al Udeid airbase, which houses the headquarters of US Central Command’s (CENTCOM) air operations. In Bahrain, an Iranian drone struck communications equipment at the headquarters of the US Fifth Fleet.

This damage raises a question about how much the US can still use these bases once they come under attack. Gerd Nonneman, a professor of international relations and Gulf studies at Georgetown University in Qatar, told Al Jazeera the war had shown that some bases were “themselves very vulnerable” and “unable to fulfil many of the tasks they were established for”.

Why bases are harder to defend

Mark Hilborne, a senior lecturer at the Defence Studies Department at King’s College London, told Al Jazeera “large bases are indeed becoming more easily targeted”.

“One of the technologies that has allowed this, alongside fairly cheap ballistic missiles, is drones,” he added.

Iran has invested heavily in developing cheap, domestically produced drones that inflict disproportionate damage to targets and exhaust far more expensive interceptor missiles.

Meanwhile in the UK, drones present US airbases with different challenges. While the nature of the reported threat to RAF Mildenhall remains unclear, the Fairford case concerns an alleged plot. “The range of actors who might target bases has changed,” Urban Coningham, a research fellow and course lead at the Royal United Services Institute (RUSI) in the UK, told Al Jazeera. “Bases are more vulnerable, and that changes the risk calculation.

“Anyone can manufacture a drone in a basement … People looking to create mischief or mayhem can recruit organised criminals, making attacks harder to attribute.”

All of that, he said, makes bases “more vulnerable, and that changes the risk calculation”.

‘Policy conundrum’

As Washington moves some military assets out of bases in the Gulf and Europe, it could also come to rely more heavily on Israel, its closest ally in the Middle East. Shabani said there were “already signs that CENTCOM is moving towards using Israel as a key forward base”.

Israel launched the war on Iran in February alongside the US. With the oil and gas exports on which Gulf economies depend at risk, keeping US forces nearby allows Washington to respond, but it also leaves those forces exposed to Iranian attacks.

“The longer-term solution is to work with partners and ensure that allied forces are ready to fend for themselves,” RUSI’s Coningham said.

“There is a debate within the US policy establishment, and the Iranians are referencing it and saying that as long as US forces are there, they are a target,” he said. “That is the policy conundrum for the US. Ultimately, they can’t see any alternative to having bases in some form.”