Enemies

Action is already starting on a U.S.-led coalition to take on Islamic State. The coalition includes European participants (not known for getting involved in U.S. military activities) and Arab nations (who often see Western military actions in nearby areas in a negative light). A decisive reaction, considering Obama's proposal on the subject was not even a week ago. It is reminiscent of early agreements in World War II, and makes one particular possibility for the Peak of the Crisis seem much more likely.

Russia is one of those listed as being involved, even though many of the other participants officially consider it as causing trouble of its own not that far away.  It's a truism, though, that the enemy of your enemy is your friend. Which goes in a couple of different directions in this case, considering that degrading ISIS is being helpful to Syria, which is supported by Russia and opposed by the United States.

 (On a previous discussion point, here is a useful summary of What Are They Thinking Anyway?)

The Soviet Union tried to stay out of World War II, and with some initial success. When they were forced into it, they were accepted (if not always trusted) as an important part of the Allies. The big war conferences are remembered as involving the United States, the United Kingdom, and the Union of Soviet Socialist Republics. Not everyone was happy about helping (or being helped by) the Commies, but working with them was a given. The same might be true here.