> and Ukraine possibly even joining at some point
That wasn't possible, and as far as I'm aware it remains impossible for now. I believe it is a prerequisite for joining NATO, that you should be in control of your internationally-recognized borders. Otherwise, at the moment of joining, the whole of NATO would instantly be at war with Russia, because NATO's supposedly a mutual defence treaty organisation.
Same goes for Georgia, as far as I can see; Georgia's internationally-recognized borders place South Ossettia inside Georgia. But South Ossettia remains occupied by Russia.
[Edit] FWIW, I don't think NATO is in shape to go to war in Eastern Europe. Western countries took advantage of the end of the Cold War and the "peace dividend" to hollow-out their armed forces and ammunition reserves. As a Brit, I'm particularly ashamed of Britain's conduct, which has involved committing huge amounts of money to two spiffy aircraft carriers, which still don't carry a full complement of F35s, and which can't operate without a fleet of destroyers and frigates, not to mention supply ships. And a new generation of strategic nuclear missile submarines. Having a stockpile of 122mm artillery shells would be massively cheaper, and a better use of money.