@Argothair:
It’s a fair question. Thematically, Russia is at war in 1939 because if Stalin wanted to invade a territory, there was nobody to tell him not to. In 1939 Russia was fighting wars in both Finland and Mongolia, and occupied the Baltic States with over 20,000 troops. It’s not as if Russia was on a peacetime footing – even though they had relatively friendly relations with Germany, they could have chosen to attack Germany in 1939 if they wanted to.
Mechanically, Russia is at war because it’s boring for the only Allied nation that can fight the Nazis to be the British. The game moves slowly enough without being told something like “Oh, by the way, all you can do on turns 1 and 2 is just reshuffle your troops.”
That said, if you want to add a house rule that says Russia can’t attack Germany until turn 3 unless Russia attacks Germany first, go right ahead.
My point is that Russia was more leaning towards axis than allies during 1939, but I would say they aren’t at war unless Germany attacks them until R2. What you could do is roll a dice in the beginning and if it’s a 6 Russia joins the axis, but america is immediately in the war. If it’s a 1 then Russia is immediately at war with the axis R1. If it’s 2, 3, 4, or 5, then they stay neutral until R2 unless there attack by Germany.