[Goose]

For defending the Baltics, I’m assuming a NATO force so the burden is not all on the US. And in an ideal world, a NATO force that includes the Finnish and Swedish navies in the Baltic Sea. And again notionally, in a world with a lot more military spending than NATO currently commits so that an armored division is not such a disproportionate commitment. Yes, there are issues with supply lines and defense in the event of a conflict, but the point of such a forward based force is to deter through mutually assured destruction. Considering Estonia is probably within artillery range of the outskirts of St. Petersburg, I’d be a lot more worried as Russia than as NATO in that scenario. Obviously, it requires an enormous commitment, but we did that and a heck of a lot more in the Cold War.

OK, I get the idea you are thinking of a world where NATO is a lot stronger in manpower. I still absolutely guarantee you NATO isn't putting an armored division in the Baltics. In Poland, quite probably. Some forward units in the Baltics, yes. It is just too easy to get cut off there. You may be familiar with the "forward defense" argument that existed in NATO near the end of the cold war. Both Britain and The US were dead set against it for tactical reasons. We eventually ended up doing it, at least on paper, because the GDR absolutely insisted on it. However, the Baltics aren't Germany and don't bring the benefits.
I am not sure if by mutually assured destruction you are referring to nuclear war or whether you mean the idea that if the US has troops in a country and any of them get killed the US is committed to the war. In either case, having some troops as "hostages" in the Baltics is what we are doing now. Placing an entire division in a tactically compromised position isn't needed to do that.
We also will be in a "He who defends everywhere defends nowhere" situation, as we were in the cold war. Our situation is also potentially both better and worse against Russia. I imagine you have seen the articles on the internet pointing out how the flat, not easily defended plain of Europe gets wider as you go East. During the cold war, NATO had to defend the Fulda gap. That was more than big enough even with the forces available during the cold war. Now NATO will have to defend from the top of Finland to the Sea of Marmara. OUCH! That is not a good tradeoff, especially considering many of the countries involved are not military giants. Germany really found this out the hard way as their lines got longer and longer North-South as they advanced further into Russia. If Russia wants to attack, they can chose the place for their maximum advantage.
On the other hand, Russia needs to defend that entire region as well. One of the reasons Russia wanted the Warsaw Pact nations was that defending on the client states Western border would be a much shorter line. For this reason, NATO is well advised to rely on a mobile force that can respond to attacks where they happen. (Which requires air superiority, just to be clear) We don't have enough troops to defend the whole front in depth even with maximal efforts. Back in the cold war days, the Russians had more troops than they do now. But even they can't defend the entire border.
The "full scale war" scenario will only happen as a result of a major miscalculation by Russia. However, one can see Russia attempting to "pick off" the Baltics because Putin has some fantasy that they should be part of Russia. NATO needs to figure out how to counter that. Similarly, Russia may feel they need part of Finland to protect the access to the Baltic Sea. Make a plan for this, but base it on tactical considerations only.

[Goose]

For defending the Baltics, I’m assuming a NATO force so the burden is not all on the US. And in an ideal world, a NATO force that includes the Finnish and Swedish navies in the Baltic Sea. And again notionally, in a world with a lot more military spending than NATO currently commits so that an armored division is not such a disproportionate commitment. Yes, there are issues with supply lines and defense in the event of a conflict, but the point of such a forward based force is to deter through mutually assured destruction. Considering Estonia is probably within artillery range of the outskirts of St. Petersburg, I’d be a lot more worried as Russia than as NATO in that scenario. Obviously, it requires an enormous commitment, but we did that and a heck of a lot more in the Cold War.

OK, I get the idea you are thinking of a world where NATO is a lot stronger in manpower. I still absolutely guarantee you NATO isn't putting an armored division in the Baltics. In Poland, quite probably. Some forward units in the Baltics, yes. It is just too easy to get cut off there. You may be familiar with the "forward defense" argument that existed in NATO near the end of the cold war. Both Britain and The US were dead set against it for tactical reasons. We eventually ended up doing it, at least on paper, because the GDR absolutely insisted on it. However, the Baltics aren't Germany and don't bring the benefits.
I am not sure if by mutually assured destruction you are referring to nuclear war or whether you mean the idea that if the US has troops in a country and any of them get killed the US is committed to the war. In either case, having some troops as "hostages" in the Baltics is what we are doing now. Placing an entire division in a tactically compromised position isn't needed to do that.
We also will be in a "He who defends everywhere defends nowhere" situation, as we were in the cold war. Our situation is also potentially both better and worse against Russia. I imagine you have seen the articles on the internet pointing out how the flat, not easily defended plain of Europe gets wider as you go East. During the cold war, NATO had to defend the Fulda gap. That was more than big enough even with the forces available during the cold war. Now NATO will have to defend from the top of Finland to the Sea of Marmara. OUCH! That is not a good tradeoff, especially considering many of the countries involved are not military giants. Germany really found this out the hard way as their lines got longer and longer North-South as they advanced further into Russia. If Russia wants to attack, they can chose the place for their maximum advantage.
On the other hand, Russia needs to defend that entire region as well. One of the reasons Russia wanted the Warsaw Pact nations was that defending on the client states Western border would be a much shorter line. For this reason, NATO is well advised to rely on a mobile force that can respond to attacks where they happen. (Which requires air superiority, just to be clear) We don't have enough troops to defend the whole front in depth even with maximal efforts. Back in the cold war days, the Russians had more troops than they do now. But even they can't defend the entire border.
The "full scale war" scenario will only happen as a result of a major miscalculation by Russia. However, one can see Russia attempting to "pick off" the Baltics because Putin has some fantasy that they should be part of Russia. NATO needs to figure out how to counter that. Similarly, Russia may feel they need part of Finland to protect the access to the Baltic Sea. Make a plan for this, but base it on tactical considerations only.