Because what got that country into trouble with Russia was it looking at us, the EU, for help in combating corruption.

Its not a question of what we should be doing from a moral point of view. From a moral point of view I fully agree: We should be doing something, though I dont think anything involving the military is an at all good idea. From a moral point of view we also should have done something about the US invading the Iraq (above frowning in a disapproving fashion, that is), we should be doing something about the illegal and gross stuff that Israel continues to get up to and so on. However, I am wondering why all of a sudden what we prefer doesnt matter anymore, as is what /u/bl25_g1 seems to be implying, when we clearly have a choice to do whatever we want to when it comes to the US' and its allies violations of international law, disregard for human rights and general international dickbaggery. Why is one nation doing it something we can, have and will freely ignore while what we prefer doesnt even matter anymore when a certain other nation happens to do it?

Now, in regards of using the military: The way I see it regardless of what we do the Ukrainian people will lose if we get out military involved in any way, since any escalation of the conflict will at the very least feature their country as a main theater of war, killing countless of civilians, destroying the infrastructure and leaving the country in ruins for a long time to come. As such, regardless of the very obvious threat of engaging a nuclear power in a military fashion any military solution we would come up with would end up being unable to fulfill its purpose - helping out the Ukrainians. So unless our goal is to shove a figurative erection of military might down another nations throat, which is a pretty American thing to do and likely a cause for the rather aggressive US/NATO rhetoric the military can be ruled out as an option from the start.

I would also like to address your point about the US being more powerful and, as such, dealing with it being more difficult for us. Thats not a good stance to take. Either the rules apply for all nations, and then we have to enforce them on all nations which would have meant economically sanctioning the US, or they dont apply for any nations in which case we dont have a good justification for sanctioning Russia. Now, that doesnt mean that we cant sanction Russia now, but it does mean that if we do go down that route, which I am very much in favor of, we will have to sanction the US the next time they start breaking international law and will have to start sanctioning all nations that are currently in the process of violating international law. That is, from my point of view, the only morally acceptable stance to take.