
https://www.project-syndicate.org/commentary/biden-must-replace-liberal-international-order-by-joseph-s-nye-2020-07

https://blogs.lse.ac.uk/europpblog/2023/06/19/is-differentiated-cooperation-the-way-forward-for-eu-foreign-policy/

https://www.nytimes.com/2019/06/06/world/europe/us-defense-spending-nato.html