Apologies for the long reply–
First, Radzinsky is NOT especially reliable. He’s a dramatist, not a trained historian, and so he tends to not let the facts get in the way of a good story, and more often spins a single fact into a long flight of fancy.
The issue of Stalin’s preparing a war against Hitler goes WAY back. The Nazis, in fact, used it as cover back in '41–i.e., that they invaded the USSR to forestall Stalin’s plans to attack them. It was revived more recently by V. Suvorov, Soviet military officer and defector, who advanced the thesis in Icebreaker and other books. It has also been backed by some German historians, who use the idea of Stalin’s aggression to try to show that Hitler was not UNIQUELY evil–that the bad things that Hitler did were on a par with what Stalin did, including waging aggressive war.
The thesis has a lot of problems, but the issue is very complex. Suvorov, for example, comes close to nut-job status–his books are wrong on lots of little things, which makes you wonder about the big things.
SO–what were the Soviets up to in 1941? Certainly Stalin felt that war with Hitler was coming, and was preparing for it. He didn’t expect it on 22 June 1941, though. Odds are he expected Hitler to do the RATIONAL thing and wait for the end of the war with Britain, rather than fight a two-front war.
Stalin did miss a lot of intelligence about German war preparations, but the issue isn’t as clear-cut as it might seem. The Germans were mounting a very effective program of disinformation that fed directly into Stalin’s preconceived idea that war with Hitler wasn’t imminent. The Germans planted info through double-agents to alter how Stalin saw the German military buildup on the Soviet border, which was quite clear to Soviet intelligence.
Essentially, the Germans planted the idea that Hitler’s buildup was in preparation for an ultimatum to Stalin demanding economic and territorial concessions. Stalin then expected that before hostilities began, he could expect demands from Hitler which he could use to further stall war and allow him time to prep. He didn’t expect that Hitler would simply attack.
The Red Army’s deployments in 1941 WERE very far forward, but to some degree that can be explained by Soviet military doctrine, which was fundamentally offensive. The defensive plan was to counter the initial attacks and launch an immediate counter-offensive, for which you’d need lots of forces in place far forward. Didn’t work out quite so well.
As several people have mentioned, the Red Army was in bad shape in 1941. David Glantz, in the book Stumbling Colossus makes the explicit argument that the Red Army was in SUCH bad shape Stalin couldn’t have been planning a preemptive strike.
That argument doesn’t quite work, it seems to me. General Zhukov, who more than anyone else won World War II for the Soviets, and had a much better idea of exactly how bad off the Red Army was, nevertheless saw the German preparations for what they were and urged a preemptive spoiling attack in May 1941. He at least thought it could work, and he was in a position to know. Stalin rejected this plan. If he was planning on attacking Hitler, it wasn’t in 1941.
Politically, though, this whole debate to shift blame to Stalin misses the point. It is abundantly clear that Hitler’s plans to invade the Soviet Union had NOTHING to do with forestalling a Soviet attack.
The best book on these issue, based on the latest research, is Gorodetsky’s Grand Delusion, but it is NOT an easy read.