Why Sanctions?

The United States and much of the European Community have placed sanctions on Russia or  individual Russians because of the invasion of Ukraine over the past few days. Why?

The obvious answer is that we are trying to prevent or punish Russia for its attacks in the Ukraine. But does it work?

Mostly ... no. The answer is that sanctions very rarely work. Once a government has committed a country to a certain extralegal path, the role of sanctions is usually baked in. There are very few sanctions that have worked. 

We see that sanctions haven't changed the trajectory of Iran, North Korea, Russia (where we already had some sanctions), Sudan or nearly any other country. So why do it?

Well...

Most governments introduce sanctions to stop or punish behavior. Countries and citizens feel like is doing something. Something big and splashy but probably not effective. 

On the other hand, what else is there to do? The western world isn't going to go to war to save Ukraine, albeit NATO did provide a lot of weapons to Ukraine. The western world won't go to war over North Korean nuclear weapons or Iranian steps to acquire a nuclear weapon. The exception to the last statement is Israel, who might actually go to war to stop Iran from getting the bomb.

The one VERY impactful sanction on Russia was implemented by Germany in stopping the Nordic gas pipeline. This will hurt most of Western Europe. But it will also deprive Russia of a LOT of income. Perhaps more than just the Nordic pipeline revenue, since most of the other gas deliveries are through Ukraine.