[XorNot]

It's only clear they're good at stopping invasions by history. You could (and possibly are) seeing the precedent set that border disputes can escalate to kinetic conflicts without nukes getting involved - the problem is no one knows where the line is and historically that kept things calm.

Who even knows if that's still the case though? If India goes after Kashmir so they genuinely think Pakistan would risk annihilation defending it if it was lost?

Russia could easily dispose of NATO as an ongoing problem by losing a war with the Baltics if the US then disregards Article 5 because "well it's just not worth risking nuclear war".

Appeasement doesn't work, but apparently we all forgot even the simplified history of WW2.