These crises have all increased cooperation within the EU to some extent:

- The Greek economy is not dead thanks to an EU debt jubilee that could not be called that way.

- The migrant crisis has increased the role of Frontex and other EU level instruments by an extent unimaginable before.

- My significant other is Latvian, lives in Belgium, got her first and second covid shot in France, and her third one in Germany.

- In this crisis, even - hm, let's call them "less cooperative" politicians- like Matteo Salvini, Mateusz Morawiecki and Viktor Orban got behind several common EU policies at political light speed.

- Did you see the recent flurry of NATO moving east announcements?

We don't have an international pact triggered by historical experience around handling refugees, or infectious disease control. We have one like that exactly for the purpose of military support. So yes, we expect NATO members to step up for protection of other members. We have joint exercises so that the forces do have common approaches and plans.

Turns out things change quickly: https://twitter.com/BBCkatyaadler/status/1498017173792514051

> EU announces it has agreed unanimously amongst all member countries to take in Ukrainian refugees fir up to 3 years without asking them to first apply for asylum.

In the end I’d say the Greek economic crisis was handled well. The things you mention are very tricky and not guaranteed to have any solutions.