Nothing except concrete military capability, defensible border positioning, and an ingrained culture of territorial defensive without offensive aspirations has

Nothing except concrete military capability, defensible border positioning, and an ingrained culture of territorial defensive without offensive aspirations has a good track record for lasting peace. Any sort of peace acceptable to the Ukrainians is going to leave Russia with a lingering casus belli, which only the above (and NATO membership) is going to prevent escalating back into war.