With the clarification provided by @dantehere, and especially this part "something like a sabotage mission or covert operation we wouldn’t consider large enough for an invasion. ", I reduce my probability for invasion of Lithuania to below 0.5% (so it rounds to 0%).
Even if by 2027 Russia has achieved their military objectives in Ukraine (however they will define them at that time) and declared victory, on a rational level, I think it is very unlikely they would want to start another confrontation this soon, and with a stronger opponent. The only scenario which comes to my mind of a large-scale invasion happening which could be considered as not violating the rational actor theory, is the one when it happens shortly after the start of the US-China military confrontation, most likely over Taiwan, especially, if China would be winning. However, a large-scale Chinese military confrontation with the US happening in this timeframe, likely would not fit into rational actor theory even if China would be confident about their military having the upper hand, because of the risks to their economy (I am not an expert on this, but I read that in Krzysztof Wojczal's book "Trzecia Dekada" and it makes sense to me). So that scenario itself seems very unlikely because there are a lot of "if" conditions to be satisfied first. Even if the US would leave NATO (again, something with very low probability - Metaculus community median is currently at 97% that the US will remain in NATO until at least January 1, 2029, I would probably say 99% here), I doubt that the US would just be watching the Russian invasion of NATO countries in Europe and doing nothing. There might be of course some other scenarios I have not thought of.
But my point is that the rational perspective (at least if we define rationality as in rational actor theory) is not everything. Before full-scale invasion of Ukraine by Russia the consensus of most of the Superforecasters was for a long time that this will not happen. I remember that I initially agreed with their rationale, that this wouldn't be a rational move for Russia, but facts on the ground made me change my mind. I remember feeling bad going against the consensus of such a wise group of people with such a great track record (people I really respect and have a few friends among them), but I decided that to learn anything, after considering all the information I have, I need to follow my thinking and my judgment wherever it leads me. Some of my Superforecaster friends also changed their view on this, and the consensus eventually changed as well. There were also superforecasters and other great forecasters who were convinced about this happening very early, but they were a minority, an exception. I remember that Metaculites have done quite a good job there, but as a community we also haven't seen that months in advance. Some members of the great Samotsvety Forecasting Team won good money on prediction market betting that this will happen - I wonder if part of the success could have been non-western centered perspective and insights of Misha Yagudin - a great forecaster who is Russian. My point here is that the consensus of so many great minds was for quite some time in its essence that Russia won't do it because it is not the rational thing to do for them.
As Robert Jervis wrote in his book "Perception and Misperception in International Politics":
"A state that is not willing to run major risks may misperceive or miscalculate and undertake very dangerous actions. The state’s behavior would not correspond then to its basic intentions. For example, the Russians probably grossly mis-estimated the risks they were running by putting missiles into Cuba. And at many points Hitler may have been reckless not because he willingly tolerated a high probability of war but because he was certain that the other side would back down. When his generals opposed his policy on the grounds that it was too dangerous Hitler did not argue that the risks were worth running. Rather he told them that the risks were slight. Indeed it may be that states that use force to alter the status quo often differ from others less in their willingness to run perceived risks than in the fact that they perceive low risks in situations where others perceive high ones."
and:
"(...) because differences in firsthand experiences lead to differences in perceptual predispositions, the chance of misperception is increased by events that one actor experiences but that others with whom he interacts know of only indirectly. Furthermore, each actor may be unable to understand how the other is perceiving and why it is behaving as it is."
Miscalculations and miscommunication happen and quite often lead to armed conflicts. I think it is safe to say that Russia miscalculated in 2022 with their initial goals, but we are yet to see how it ends for them in the long run. Other example which comes to my mind is Iraq invading Kuwait. Here is the long quote from "Debriefing the President: The Interrogation of Saddam Hussein" book by John Nixon a CIA analyst who interrogated Saddam Hussein after his capture in 2003:
Saddam was forever puzzled by his country’s relationship with the United States. When we talked about U.S.–Iraqi relations, Saddam often got a perplexed look on his face, as if he was still trying to figure out where the relationship went wrong. “The West used to say good things about Saddam,” he said. “But after 1990 all that changed.” (Interestingly enough, this comment was echoed by officials from the George H. W. Bush administration during an NBC roundtable discussion on the twentieth anniversary of the Gulf War. Brent Scowcroft, who was national security adviser, said that after 1990, Saddam just changed. James Baker, the former secretary of state, shook his head in agreement. They couldn’t understand why. Things had gone along well in the 1980s, but somehow Saddam changed. Saddam had remained remarkably consistent in his governing and his penchant for doing the unpredictable. The Bush 41 administration had been caught unaware by Saddam’s foray into Kuwait. I strongly doubt that if Washington had made it clear to Saddam what it was willing to do to reverse any hostile Iraqi move against Kuwait, he would have crossed that red line.) Pointing out that America had supported Iraq during the Iran-Iraq War, Saddam said, “If I was wrong, why did the U.S. support me? If I was right, why did they change?” In Saddam’s mind, it was the United States that had suddenly and inexplicably changed course. “Iraq had a good relationship with the U.S. in [President] Reagan’s time, but it took a wrong turn during the [Bush] father and son era,” he said. “I saw the day in the 1950s when Iraqi youth would line up for information about America. Now what does it look like? The embassies all have guns.”
So my main point here is that I think we should be looking at how the current war between Russia and Ukraine can affect these misperceptions between Russia and NATO in the future.
We all talk about how Russia doesn't have red lines, and how the western politicians are gradually overcoming their mental barriers regarding what types of weapons can be provided to Ukraine and how Ukraine can use them against Russia. However, we should also be thinking about how this affects Russians perceptions and how it can cause misperception.
Russians are told by their government and media that they are fighting NATO, and they not only see NATO equipment fighting them in Ukraine, but now after the Kursk offensive also in their own territory (not to mention that many of them undoubtedly perceive occupied parts of Ukraine as Russian territory, but this still must be kind of next level of confrontation for them). And in a way, they are fighting with NATO, as NATO provides weapons, ammunition, intelligence, money, training and other supplies and support to Ukraine. So, I think for Russians and Russian soldiers and officers, armed confrontation with NATO soldiers may be easier to imagine and accept as an act, than before the full-scale invasion of Ukraine. Would a kind of mirror-imaging cause them to think the same about NATO red lines as we now think about theirs? Would their own experience lead them to doubt the resolve of NATO countries to follow Article 5 over things like soldiers crossing Baltic country border? I don't know, but I believe we should be thinking about that.
With the clarification provided by @dante here, and especially this part "something like a sabotage mission or covert operation we wouldn’t consider large enough for an invasion. ", I reduce my probability for invasion of Lithuania to below 0.5% (so it rounds to 0%).
Even if by 2027 Russia has achieved their military objectives in Ukraine (however they will define them at that time) and declared victory, on a rational level, I think it is very unlikely they would want to start another confrontation this soon, and with a stronger opponent. The only scenario which comes to my mind of a large-scale invasion happening which could be considered as not violating the rational actor theory, is the one when it happens shortly after the start of the US-China military confrontation, most likely over Taiwan, especially, if China would be winning. However, a large-scale Chinese military confrontation with the US happening in this timeframe, likely would not fit into rational actor theory even if China would be confident about their military having the upper hand, because of the risks to their economy (I am not an expert on this, but I read that in Krzysztof Wojczal's book "Trzecia Dekada" and it makes sense to me). So that scenario itself seems very unlikely because there are a lot of "if" conditions to be satisfied first. Even if the US would leave NATO (again, something with very low probability - Metaculus community median is currently at 97% that the US will remain in NATO until at least January 1, 2029, I would probably say 99% here), I doubt that the US would just be watching the Russian invasion of NATO countries in Europe and doing nothing. There might be of course some other scenarios I have not thought of.
But my point is that the rational perspective (at least if we define rationality as in rational actor theory) is not everything. Before full-scale invasion of Ukraine by Russia the consensus of most of the Superforecasters was for a long time that this will not happen. I remember that I initially agreed with their rationale, that this wouldn't be a rational move for Russia, but facts on the ground made me change my mind. I remember feeling bad going against the consensus of such a wise group of people with such a great track record (people I really respect and have a few friends among them), but I decided that to learn anything, after considering all the information I have, I need to follow my thinking and my judgment wherever it leads me. Some of my Superforecaster friends also changed their view on this, and the consensus eventually changed as well. There were also superforecasters and other great forecasters who were convinced about this happening very early, but they were a minority, an exception. I remember that Metaculites have done quite a good job there, but as a community we also haven't seen that months in advance. Some members of the great Samotsvety Forecasting Team won good money on prediction market betting that this will happen - I wonder if part of the success could have been non-western centered perspective and insights of Misha Yagudin - a great forecaster who is Russian.
My point here is that the consensus of so many great minds was for quite some time in its essence that Russia won't do it because it is not the rational thing to do for them.
As Robert Jervis wrote in his book "Perception and Misperception in International Politics":
and:
Miscalculations and miscommunication happen and quite often lead to armed conflicts. I think it is safe to say that Russia miscalculated in 2022 with their initial goals, but we are yet to see how it ends for them in the long run.
Other example which comes to my mind is Iraq invading Kuwait. Here is the long quote from "Debriefing the President: The Interrogation of Saddam Hussein" book by John Nixon a CIA analyst who interrogated Saddam Hussein after his capture in 2003:
So my main point here is that I think we should be looking at how the current war between Russia and Ukraine can affect these misperceptions between Russia and NATO in the future.
We all talk about how Russia doesn't have red lines, and how the western politicians are gradually overcoming their mental barriers regarding what types of weapons can be provided to Ukraine and how Ukraine can use them against Russia. However, we should also be thinking about how this affects Russians perceptions and how it can cause misperception.
Russians are told by their government and media that they are fighting NATO, and they not only see NATO equipment fighting them in Ukraine, but now after the Kursk offensive also in their own territory (not to mention that many of them undoubtedly perceive occupied parts of Ukraine as Russian territory, but this still must be kind of next level of confrontation for them). And in a way, they are fighting with NATO, as NATO provides weapons, ammunition, intelligence, money, training and other supplies and support to Ukraine. So, I think for Russians and Russian soldiers and officers, armed confrontation with NATO soldiers may be easier to imagine and accept as an act, than before the full-scale invasion of Ukraine.
Would a kind of mirror-imaging cause them to think the same about NATO red lines as we now think about theirs? Would their own experience lead them to doubt the resolve of NATO countries to follow Article 5 over things like soldiers crossing Baltic country border? I don't know, but I believe we should be thinking about that.