The West is like the Titanic
And Russia is like the iceberg cutting through it. Three lowest decks are already flooding: Ukraine, Moldova, and Georgia. Pressure is currently highest in Ukraine, but there's no reason for the water to stop there. Some decks, especially those to be flooded next, are helping a lot, some help a little, and some see this as somebody else's problem. US is the highest first-class deck where people refuse to believe the water could ever rise all the way to the top.
To stop the flooding (the Russian army), it is necessary to seal off any breaches (defend the front line) and to pump out all the water that already got in (liberate the currently occupied land). Ukraine happens to be one of the most resourceful decks, but even they cannot stop the flood on their own. It is necessary to orchestrate concerted effort, in which all decks take part, but herein lies the problem.
The West, like Titanic, is a very big ship and many people just don't believe it can sink and hence see no reason to act. It is subdivided into a number of countries with borders functioning akin to Titanic's compartments, giving false sense of distance, independence, and security. Many people, both individually and collectively on country level, take advantage of the situation to temporarily enrich themselves, skirt their duties, or succumb to psychological failures of denial, distraction, distrust, and despair.
Russian leadership of course knows all this and senses an opportunity to pull the old Roman divide-and-conquer strategy against the West. Russia cannot challenge the West all at once, at least not without great risk, but it can take on individual countries one by one the way flood reaches higher and higher decks. With every conquered country, Russia becomes stronger and more resourceful while the West becomes weaker and the process accelerates.
Some people think it will stop in Ukraine. They want to seal off the flooding deck and forget. But that's not how it works. If Russia succeeds in Ukraine, it will invade Moldova and perhaps Georgia immediately afterwards. These countries stand no chance without direct involvement of NATO, which the West has already shown to be unwilling to do. If the West is unwilling or unable to supply weapons to the front lines in Ukraine, it is very unlikely to be willing and able to defend Baltic states with live force in unfavorable geography. Once Russia proves in Baltics that NATO is unable to defend its own borders, nothing will discourage it from invading other countries in eastern Europe, likely in the Balkans followed by Slovakia and then Poland.
Many of you probably think that I am already stretching it with invasions beyond Baltic states. Russia might look tiny when you compare it to the West by GDP, but GDP means nothing during war. Most of that western GDP comes from licenses and services (think banks) whereas Russian GDP is all about natural resources and defense industry. In war conditions, spending on licenses and services drops while spending on natural resources increases. If the war is large (think WW3), ensuing pressure on prices can swing GDP ratio between Russia and the West by a factor of ten within days. We have seen a preview of this phenomenon when prices of energies spiked after Russia invaded Ukraine.
Now, of course, the West is not devoid of natural resources. It is reasonably rich in resources and it has sizeable and skilled workforce that can transform the resources into military power whereas Russia already suffers from labor shortages and it has to export its resources to make good use of them. West also ultimately possesses much larger mobilization potential. That makes things look optimistic for the West, but this is where the drone wars, artificial intelligence, and automation come in. Current economy is mostly labor-constrained, but all the automation that is ahead of us reduces value of workforce while increasing relative value of natural resources, gradually transitioning the economy into resource-constrained mode. Automation technology relies on skilled workforce, patents, and trade secrets, which currently plays into West's cards, but technology diffusion cannot be delayed for more than a few years and artificial intelligence will eventually replace most of that skilled workforce. Finally, drone war does not need much live force. It just needs steady flow of supplies from arms industry fueled by plentiful natural resources.
I am explaining all of this to you to show you that size advantage of the West is at best temporary, at worst imaginary. You need to understand this to see that the prospect of Russia invading country after country is very real. Returning to our Titanic analogy, as the water was rising through the ship, flooded parts lost their buoyancy and their weight only accelerated the flooding. Meanwhile parts of the ship still above water were getting smaller and less resourceful in coping with the situation. Something similar will happen with the West if Russia is allowed to continue its conquest. Conquered territories will add to Russia's strength. We see that already in occupied parts of Ukraine, which are milked for resources and manpower. Something similar is happening within Russia with ethnic minorities and their historical lands. On the other side of the front line, loss of territory will gradually weaken the West. Every country attacked after Ukraine will be harder and harder to defend. By the time millions of Russian drones start flowing into Alaska, Russia will be so big and the West so weak that Russia will be able to simply exhaust whatever is left of the West with crude attrition.
So what about nukes? I wouldn't put much trust in nuclear weapons. In the West, only US has sizeable number of nuclear weapons and there's no way US citizens would permit their use for anything other than nuclear deterrence. Meanwhile, Russia is much more relaxed about the prospect of nuclear war. It has less to lose. In the endgame, Russia would attack US, which would justify use of nuclear weapons, but by that time, Russia could just weather the nuclear war knowing it would be the ultimate winner. Remember that Russian leadership thinks in terms of centuries. They are okay waiting for radioactive contamination to clear naturally. Given the Russian determination to go to nuclear war if necessary, US citizens would likely accept some sort of compromise surrender over a foolish and ultimately pointless nuclear last stand. The same logic applies to all weapons of mass destruction.
At this point, it's worth briefly mentioning the so-called "neutral" countries. They are threatened by Russian imperialism as much as the West is, but just like people in the West, they mistakenly believe it's just some local, contained conflict in Ukraine, from which they can safely profit. Country leadership should be better informed, but it is often corrupt just like in the West or distracted by smaller but more imminent fires. "Neutral" countries are of course wrong in discounting importance of what is happening in Ukraine. Expanding Russian empire would get to them eventually too. Russia doesn't have unfinished business with Europe. It has unfinished business with the entire world. Many African countries already feel the heat as Russia tries to control their access to agricultural exports from Ukraine and sends in mercenaries to prop up authoritarian regimes. Given this context, supporting Russia in any way amounts to treason no matter which country you are in.
Whether the metaphorical western Titanic sinks or not is yet to be seen. Defeat is not inevitable just like sinking of the real Titanic ship wasn't inevitable. To avoid this fate, we need awareness and understanding of the situation, a realistic success plan, shared commitment to its implementation, organizational structure to execute it in coordinated manner and without hesitation, and collective effort (and some sacrifice) of sufficient intensity. That's a tall order for the disorderly bag of cats that the West is, but it's necessary if our grandchildren are to have a future.