My growing belief is that practical geopolitical considerations take priority over moral questions about the rightness / wrongness of confronting Russia, most of which are academic in my opinion.

For one thing, a permanent NATO presence would force Russia to maintain a large(r) standing army along the Ukrainian border. Russia's economic problems, while somewhat overstated, are not insignificant, and a massive troop deployment could hurt it in the long run. A Russia that's less capable of funding its outlying regions risks secessionist movements. And the secession of eastern Siberia, along with its vast resources, would push that part of Asia into the Chinese sphere of influence. The Caucasus, southern Russia, and central Asia would risk being overrun by Islamist movements. And if not, they would gravitate towards Turkey and China, whether by choice, by compromise, or by threat.

I say that Russia's economic problems are somewhat overstated, and that's because American sanctions have hardened Russia's economy, simultaneously making it more self-sufficient and forcing it to turn to China. As early as the Obama administration, Russia and China have been trading in their own currencies instead of the dollar, bypassing SWIFT. While not yet a major phenomenon, it's a bigger threat to American interests than maintaining Ukrainian neutrality. More sanctions would only accelerate this trend. American sanctions on Iran have had the exact same effect, pushing Iran into closer relations with China.