After weeks of watching supposed allies trade allegations of betrayal and of insulting each others' troops, delegates to the NATO Summit in London this week might be wondering who their friends are these days.
But bitter as the recriminations have been, there's an even bigger cloud hanging over the summit: doubts about the fundamental principle of trust upon which NATO was built 70 years ago.
For decades, the 29 countries making up NATO have been reassured by the treaty's ironclad guarantee of mutual defence in Article Five of its founding charter: "an armed attack against one or more of them in Europe or North America shall be considered an attack against them all."
But in the era of U.S. President Donald Trump, governments now have doubts about the United States' commitment to Article Five. The mutual defence clause has only ever been invoked once — by Canada on behalf of the U.S. in the immediate aftermath of the September 11, 2001 terrorist attacks.
The 158 Canadian soldiers and seven Canadian civilians who lost their lives in Afghanistan died upholding Article Five. The NATO alliance only works when members trust that others will answer when the call comes.
Military analyst Dave Perry of the Canadian Global Affairs Institute said NATO allies still trust the U.S. military, American institutions and the individual Americans they work with in the alliance.
"The concern is really about a president who keeps demonstrating, over and over again, that he has a very different view of how America should be relating to its allies," he said.
"The American president has left the impression at times that he's got better relations with the Russian president than he does with some of the heads of NATO allies in Europe or even Canada."