[Oorang]

I think that perhaps Ukraine was the keystone Q mentioned several times.

1997 there was a book published titled "Keystone in the Arch": https://www.brookings.edu/book/keystone-in-the-arch/

Since the publication it is quite frequently referenced in discussions regarding foreign affairs.
"Precious few books or articles do justice to both the core challenges facing Ukrainian foreign policy and the reasons Ukraine's success or failure in meeting them matters to the rest of Europe. Garnett's book does." -Foreign Affairs

"A timely and incisive book on an issue of vital importance to Europe's stability by a creative yet realistic geopolitical analyst." -Zbigniew Brzezinski, Center for Strategic and International Studies

There is also Keystone Human Services that is doing a lot of fundraising and humanitarian services for Ukraine:
https://www.khs.org/our-support-for-ukraine/

Another publication (from the Centre of Eastern Studies) regarding Ukraine, from 2016, titled Keystone of the System:
ublikacje/point-view/2016-08-18/keystone-system-old-and-new-oligarchs-ukraine

[little jeremiah]

You are an awesome source of knowledge.