Comment by Mutjake

The unfortunate side-effect is also that as US does not honor guarantees given in the Budapest memorandum, no country is going to give up nuclear weapons trusting contracts, and that European nation states (and possibly Canada, Mexico) will draw the conclusions on how to best get functional security guarantees ie. have own nuclear stockpile. This has been the status quo USA has bought by being a security provider, and by betraying it the downside is to returning to the nuclear armageddon scare of the cold war — if a European country nukes Russian territory, the retaliation might well bite back to the US soil. If Europe got too cozy with conventional warfare capabilities, the US got too cozy with the idea that they’re providing security out of the goodness of their hearts instead of it being a geopolitical bargain where they receive certain advantages as well.