This topic is news to me - anyone care to summarise the argument of "Icebreaker"? I'd understood Stalin to have been completely surprised by Barbarossa and unwilling to believe Hitler's aggression. That doesn't quite fit with someone who was planning similar action of his own. Add to that the Red Army's very limited capabilities, having lost much of its officer corps to the purges, and a "steamroller" plan does not seem very plausible. I've always regarded Stalin and his successors as essentially defensive in posture, despite their large arms spending.