Many tell us what to think. I ask my readers to be skeptical. Question me and others. 
The Western politicians and pundits do not know the history and do not understand Russia. It is not about NATO but about money. In my article “Why do most Westerners misunderstand Russia?” I explain the historical context.
Putin wants Ukraine because it is an industrialized and potentially rich country. The fertile Ukrainian farmland is one of the best worldwide. Donbas is one of the most industrialized regions of the former Soviet Union. Ukraine does not have gas and oil but has coal and iron ore. Last, it has a well-educated and entrepreneurial workforce.
When gaining independence in 1991, Ukraine was richer than Poland in most economic factors. In the following years, the Polish economy catapulted, Ukraine’s sunk. I show charts in my article “Ukraine — the world is watching.” Millions of Ukrainians visited Poland; many of them work there. In vocabulary, the Ukrainian language is closer to Polish than to Russian. Hence, Ukrainians can easily understand how things are done in Poland and ask themselves the obvious question: Why can we not do the same?
After becoming independent, Ukraine opened to the worldwide market, and often, Western connections offered better deals. In 2013, Ukraine selected to loosen its post-Soviet economic ties with Russia and advance its economic ties with the European Union. Russia saw it as a financial loss. Russia could expect that if Ukrainians followed the path of Poland, within the next 20 years they could become an industrial powerhouse. Putin is smart enough to know that the corrupt Russian economy would lose in that competition.
Russia responded by taking Crimea and stirring trouble in Donbas. Before that, no one talked about Ukraine joining NATO. After that, with the new Russian threats arriving, it became obvious that Ukraine might not survive without the NATO guarantees.
The Russians’ talk about NATO and missiles is simply pulling the wool over the eyes of Westerners. No one wants to take any Russian territory. Everyone in the West wants to do business with Russia. But some in Russia believe that Russia’s prosperity lies not in joining the worldwide economy but in extorting tributes from the vassal countries like Ukraine or Kazakhstan. President Putin supports that concept of Russia continuing the imperial Soviet policy. I write about it in the article “Is Russia an evil empire?”
Some in the West would give up on Ukraine to please Russia, making Eastern Europe nervous. Everyone asks who will be the next after Ukraine. If today’s world accepts the proposition that Russia can build its prosperity on tributes from the nations in its sphere of influence, then to prosper, Russia needs new vassal nations. The running joke now is: “Where is the border with Russia? Anywhere Russia wants it.”