What follows may seem obvious but I have gotten some pushback on twitter about why the US is involved in the crisis in Ukraine and have seen similar stuff mentioned in Canada. So what is at stake here for those on the other side of the Atlantic?
To be clear, there is a bright, shiny line between Ukraine on one side and the Baltics/Poland/Romania on the other, so we care about stuff on one side of the line for one reason and stuff on the other side of the line for another.
What is that line? Who is and who is not in NATO. The deployments of American, Canadian, and other planes, ships, and soldiers are being sent not to Ukraine but to those NATO countries nearest this brewing crisis. Why? Because the heart of NATO is Article V--an attack upon one is equal to an attack upon all. Why Dave and I have written a book that shows that this guarantee is not quite so determining, it is still quite important. Enlargement of NATO meant that this comment was extended to the new countries with Russia very much in mind.
So, countries are sending forces to these members to reassure them and to send President Putin a message--that we react differently to the plight of a member than to a non-member, so whatever he has mind should stop at the border between Ukraine and the NATO members. And this is message sending--none of the forces could actually do much to stop a real Russian attack.
I have mentioned that the Canadians have done the very least they can do--six planes (the smallest basic package), one ship (to somewhere near the region), and now one platoon to an exercise. Doing much less would mean doing nothing. The US has sent essentially the very least it could--one battalion from a unit already based in Europe, divided into four smaller hunks to be placed in the three Baltic countries and Poland.
But why should we care about what happens on the other side of that bright, shiny line? Russia's moves have undermined a basic and important principle that has helped to keep much of the peace since the mid-1970s: the use of force to change boundaries is unacceptable. The Helsinki Agreements helped to manage the Cold War by recognizing the existing boundaries of Europe. Yes, some fudging then ensued with the peaceful unification of Germany. One reason why countries recognized Croatia and Bosnia in 1992 was to give them the same kind of normative protection. The norm did not directly reverse Serbian gains at the time, but did help to buttress the eventual NATO effort.
For most of the world, the end of conquest is a pretty good deal. It helps to explain why so many countries exist today when so many of them could easily be conquered. So, it is not just Canada and the US and a few allies, but much of the world that is horrified by Russia's aggression. One can argue as much as one wants that the US is hypocritical given the 2003 invasion of Iraq. Yet as ill-conceived as that war was, it was not a war of conquest and annexation. Regime change is not quite the same thing as conquest.
Plus two wrongs do not make a right. Russia is clearly in the wrong here. If Russia was genuinely concerned about the plight of its kin, there were other measures they could have taken besides subversion and annexation. No, this is irredentism--an effort to claim "lost" territory.
There is often much joking about the Spider-man principle of International Relations--that with great power comes great responsibility, but the reality is that if the US does not respond, who will? The world always looks to the US to act when there is some action needed, even as the world is concerned about what the US does when it acts. It is a difficult problem, but, in this case, the US has a pretty clear role both due to its alliance obligations and due to its position in the world. Canada, as a member of NATO and as a country that deeply buys into multilateralism and into keeping the peace, has a role as well.