Was Hitler Right to Invade Russia in '41?

Was Hitler right to invade Russia in 1941? 

It is commonly believed that the invasion of Russia was one of Hitler's greatest strategic blunders. Up to that point the German war machine had conquered and subjugated all her enemies (except for Britain), while at the same time Russia had been providing her with much needed resources such as oil and wheat. England's position was deteriorating quickly and the United States was still neutral. The invasion of Russia cut off those precious supplies, and even though the Russians took unprecedented losses the Germans ultimately failed to take Moscow and suffered heavily in the winter that followed. While this event is usually judged by the results, it must be remembered how close the Russians came to collapsing, and had Hitler had concentrated on taking Moscow instead of switching the axis of advance during the campaign, the Germans would have likely won the war. The invasion of Russia in 1941 offered Hitler the best chance of winning World War 2. 

To understand why Hitler invaded Russia it is necessary to go back to the spring of 1941 and look at the general situation in Europe. After lightning campaigns against his enemies, Hitler controlled Western Europe, Central Europe, Scandinavia and most of Eastern Europe. A further campaign against the Balkans during the spring secured his southern flank. After witnessing its continental allies fall one by one, England was fighting for mere survival, never mind taking the fight to the enemy. This left Germany with only two major threats, the United States and the Soviet Union. The former was neutral and wanted nothing to do with what it saw as a purely European conflict, but the latter was just across the border and fielded the biggest army in the world.