If Poland or Romania had marched into Ukraine from the west, they could have easily annexed lots of fertile land and valuable cities.

I cannot imagine their leaders to be too dumb to recognize the opportunity, so there must be some actual reason. Is it just hate for Russia?

  • 6
    The title asks why Poland and Romania sided with Ukraine, but the body asks why they didn't launch their own invasions independent of Russia's. Those feel like two separate questions IMO. Not invading Ukraine doesn't necessarily equal siding with Ukraine.
    – F1Krazy
    Sep 13, 2023 at 10:27
  • @F1Krazy the body asks why they didn't seize the once-in-a-lifetime opportunity of joining in on the invasion and change borders (which, as others stated truthfully, is frowned upon in normal times)
    – Haukinger
    Sep 13, 2023 at 15:41

4 Answers 4


There is a consensus in Europe that state borders should not be changed through the use of force. It is stated clearly in OSCE documents.
Poland and Romania are both OSCE members. They also benefit from this consensus. The risk of opening territorial disputes with Germany (for Poland) and with Hungary (for Romania) exceeds the possible gains on Ukrainian land. At least I hope we all learned that much from World War II.

  • Attacking another sovereign country, especially for a land grab, is a gross violation of international law. It will make you the pariah of the world (and even risk a UN military intervention). Most countries recognize that in the modern interconnected world, this is a stupid idea, and rather choose to be good citizens.

  • Experience from recent history (directly involving some of the countries you mention) shows that military aggression only leads to distruction and misery for all concerned, not the least the aggressor. It is much more profitable to maintain friendly relationship with your neighbours in a spirit of cooperation and mutual respect.

  • The value of the land is largely created by those who work it. Do you think they will work it for you if you kill their loved ones, neighbours, and compatriots, and deprive them of their country and their freedom? You will not get “lots of fertile land and valuable cities”, but a permanent guerilla war on your hands.


Aside from the moral angle, and that not all politicians are sociopaths who consider invasion and mass war crimes to be an acceptable means of conducting foreign diplomacy, there are also a few more direct issues with this.

  1. Internal politics. War is costly to conduct, placing a strain on the economy, while also causing deaths on your own side. Most civilians don't particularly like this, especially when the goal of the war is stabbing a neighbor in the back purely to acquire some additional resources. Poland and Romania are democratic countries, and starting a war like this has a good chance of seeing the politicians who did it replaced.
  2. Friction with western allies. Supporting Ukraine is currently considered to be a priority among other Western governments, including the primary leaders in the EU and NATO. While the full diplomatic consequences are difficult to predict, it will likely end up with large-scale sanctions against the countries, and might even see movements start to remove them from the EU and NATO, though whether these succeed is a different question. Regardless, it will seriously isolate them from their current economic and military allies.
  3. Russia's response. While Russia would probably appreciate Poland and Romania getting more aligned with it, it would specifically like these countries to be under Russia's direct influence and control. Suddenly being excluded from the western club might make them very vulnerable here. What's more, Russia might also not appreciate other countries taking a bite out of the country it wanted under its own control, and seems to consider Russian territory, especially not when this might bring NATO countries with apparent aggressive intentions a lot closer to its own borders.

All in all, aside from any moral standpoints, Poland and Romania going after Ukraine would place them in direct conflict with their main allies, with economic sanctions likely doing far more damage than conquering part of Ukraine would offset, while also causing internal political issues, and leaving them vulnerable to another regional power which would be more than happy to turn them into its direct vassal states.

Far better to instead aid the country currently fighting the main threat to them, allowing them to weaken that country without expending the lives of their own citizens, while at the same time boosting their standing with their allies and getting the diplomatic credit for other benefits down the line.


This question is not as simple as it sounds, and certainly does not deserve the downvotes it is getting. During the World War II, both Poland and Romania would participate in taking chunks off of weaker neighbours as they were being dismantled by somebody else.

The answer is, likely, that both Poland and Romania value their membership in the EU, and good standings with the USA, much more than they value any new lands they could have acquired in the described fashion. Both EU and US are fairly strong on inviolatable borders, and especially against any border incursions unauthorized by them.


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