They still can of course, all they need to do is collectively start selling off their US treasuries. The US is at a highly vulnerable and precarious point with their potential bond market debt spiral situation, and this is a point of leverage that can be exploited to encourage improved behavior from a bully.
This capital can then be reallocated into domestic investment to continue to decouple from the US. Very similar to how Germany learned the hard way that buying fossil gas from Russia wasn’t going to prevent aggression. Canada has started this with their recently announced energy investment plan, Europe can do this with Eurobonds.
PM Carney announces largest clean energy investment in North American history - https://news.ycombinator.com/item?id=49339577 - August 2026
China and Canada Energy Pact as Canada Aims to Cut Reliance on US - https://news.ycombinator.com/item?id=46640932 - January 2026 (a component of China’s next five year plan includes LNG infra investment to support imports from Canada)
On Eurobonds:
Macron says €300B in EU savings sent to the US every year will be invested in EU - https://news.ycombinator.com/item?id=46722594 - January 2026 (207 comments)
https://news.ycombinator.com/item?id=46708337
(Canada and Europe collective hold ~$9T in US treasury debt, almost 25% of total outstanding debt)
Couldn't the US buy back more bonds through QE than any foreign country could sell?
This is a classical problem. In theory it works when majority of the players work together and move in same direction, however everyone being opportunistic here makes in infeasible from long term perspective. Europe itself is in a difficult stage, its dealing with Russia on one end, has trust issues with China and now the its long term partner has gone rouge. The result of all this would be a mandate to be self sufficient aka anti-globalization