I agree that even if the "crippling sanctions" that have been promised are imposed on Russia for invading Ukraine are actually put into place there is no real chance that will get Russia to call off its war. But isn't the point to make an example of Russia so these kinds of invasions don't seem worth it to other countries who might be contemplating a similar thing? If Russia successfully topples the Ukrainian government and installs a pro-Putin Ukrainian figurehead as president without suffering long term economic costs, maybe, for example, China would think it could get away with something similar with Taiwan.
The post WW2 international system was designed to end wars of conquest. And it has, for the most part, over the last few decades. Iraq's attempt to erase Kuwait in the 1990s was viewed as a challenge to that modern norm, which is what kicked off all those Saddam-Hitler comparisons and got most of the world on board with the first Gulf War. Sanctions don't have a good track record of changing the behavior of the nation targeted with sanctions. Once countries go down the path that triggered the sanctions, they are usually pretty committed and have a hard time backing down at that point. But if another country is considering some action in the future, maybe understanding there could be a severe economic costs might tip the cost-benefit analysis in a better direction.
