Something deeper is wrong

London has yet to outline a path to meet the NATO standard of spending 3.5% of GDP on defense by 2035 — up from its current level of around 2.7%. It has also been shut out of a subgroup within the alliance convened by Pentagon policy chief Elbridge Colby. The group is slated to meet again in Poland some time later this month.

Late last month, Colby hinted at that frustration with London, saying the countries' long history will continue to bind them, but the British government needs to make the case to its people for spending more on defense.

“There's this incredible legacy, and that's what we want to rekindle,” Colby said. “Exactly how you convince the British people [to spend more on defense] I would not presume to say, but … there's probably sort of a degree of reconciliation between what the U.K. wants to be doing, what it spends, and what it spends on, because you know a modern military is not cheap.”

The U.S. is also conducting a sweeping review of its posture in European NATO countries — including the U.K. — which will determine the number of American troops and military assets on the continent.

Sophia Gaston, a senior national security researcher at King’s College London, said: “The Trump administration is undeniably sensitive to the costs of the Iran conflict as they head into the midterms next month, so their caution is understandable.

“It’s also hard not to, at some level, perceive a degree of uncertainty about the capacity of the British services to currently prevent such an attack. That partly reflects the innate challenge drones and other aspects of modern warfare pose to the sitting ducks of expensive kit.