The circumstances surrounding the attack on Russia and the attack on the Soviet Union were entirely different. During World War I, the Tsar's popularity had already steadily been in decline due to his inability to resolve land issues, and rising protest in the intelligentsia, worker and peasant classes. The loss at Tsushima to the Japanese, Lena Gold Field Massacre, and the murder of some civilians at the Bloody Sunday protests had weakened the Tsar's standing in society. The image of Russian royalty was further tarnished by the arrival of Rasputin, and the Tsarina's reported (although disputed) sexual relationship with him.

That said, the war still did not -break- Russia as implied in the question. Russia was already fragmenting in the early 1900s, and it is arguable that the war just provided the circumstances for the revolution to occur. With the celebration of 300 years of Russian rule and the outbreak of war, support for the Tsar and Russian royal family increased. This was quickly overshadowed by losses in the war, particularly when Nicholas assumed control over the Russian forces and they continued to lose. Between the losses on the front, Rasputin's shadow, and the perceived excesses of the Romanov family, Russia was primed for a revolution. Yet surprisingly, the trigger for the revolution was inane. After a serious of particularly cold days in Petrograd, crowds took to the streets to enjoy the sun. Amongst these were protestors and agitators who managed to establish a crowd looking for change. When the military failed to suppress the protestors, and many joined their side, Nicholas' fate was sealed.

Again though, it must be made apparent that the war was simply continuing a process that was already occurring in Russia. Nicholas’ abdication passed control of Russia to the Provisional government, a government who were still committed to maintaining the war. It would only be the October Revolution, championed by Trotsky and Lenin, that would lead to the Russian withdrawal under the Treaty of Brest-Litovsk. The second phase of this revolution had its seeds established in the early 1900s when the Bolshevik and Menshevik agitation began. Yes, the war did provide the opportunity for these events to happen, but they did happen in a country that was already focused on tearing itself apart.

Moving forward to World War II, and the circumstances are entirely different. Stalin’s rigid grasp of power, overt propaganda, and use of terror, generally ensured that the population were willing to support him. The reasons for this happening are numerous, but it is worth noting the Soviet Union came perilously close to losing large cities, which would have had a disastrous impact on their ability to wage war or maintain their government.

So what allowed the Soviet Union to survive? If anything, external circumstances provided some relief and allowed for Soviet resistance.

Hitler’s tactical decisions played a key role in allowing the Soviet Union to resist. Historian’s such as Max Hastings and Anthony Beevor have focused on the potential for German forces to have, at the very least, directly assaulted Moscow, and perhaps captured it. Hitler’s orders slowed his forces, as elements of Army Group Centre were shifted southwards. This halt allowed for the consolidation of Soviet forces, reinforcement, and an increase in morale as Stalin ordered his troops to fight and stand fast. More importantly, the halting of the forces impacted Germany in two key ways. It prevented the Blitzkrieg tactics which had turned Soviet forces to retreat, and allowed for the onset of cold weather. While it is often discussed how much the Soviet winter impacted the outcome of the war, the difficult days tended to be those where warmer weather thawed the earth and Panzers would turn it to slush. In conclusion to this point, Hitler’s tactics irrevocably shaped the course of the war and allowed for Russian to stall, then counterattack. Without this, the fate of the Soviet Union -may- have been different. **I write Hitler’s choices, but realistically his generals who were unwilling to stand up to him, sycophants, or outright supporters, bear as much responsibility.

The nature of Barbarossa itself is key to understanding the ability of Russia to resist. When the German forces launched their attack through the Soviet Union, they did this with little to no discrimination regarding who ‘the enemy’ was. Treatment of those within occupied territories was horrendous for all civilians, not just Jews. Bevin argues this point:

Bevin, A. How Hitler Could Have Won World War II
‘His most disastrous error was to go into the Soviet Union as a conqueror instead of a liberator. The Soviet people had suffered enormously at the hands of the Communist autocracy for two decades. Millions died when the Reds forced people off their land to create collective farms… The secret police punished any resistance with death or transportation to horrible prison Gulags in Siberia… Life for the ordinary Russian was drab, full of exhausting work, and dangerous. At the same time, the Soviet Union was an empire ruling over a collection of subjugated people who were violently opposed to the rule of the Kremlin. Vast numbers of these people would have risen in rebellion if Hitler’s legions had entered with the promise of freedom and elimination of Soviet oppression...’

There is much truth to this idea. Hitler did not offer support for those people who were willing to overthrow Stalin in the same way Nicholas was. The atrocities inflicted on those who could potentially unite to resist Stalin were too great. The Soviet Union was able to craft propaganda playing upon these fears of being conquered by Germany (fears that were legitimate). Not only was the war in the east ideological, but it was also a war of annihilation for many. Faced with this, what choice did they have but to back Stalin?

The nature of the government is also an important consideration to this question. While Nicholas had 300 years of the Romanov legacy behind him, he did not rule with the absolute iron fist that Stalin used. Stalin had purged potential threats during the 1930s, even those were allies at one point. This surrounded him with vigorous Communists and Stalin worshippers in positions of authority, particularly through the armed forces. This weakened the Soviet military, and it would not be until the counterattacks of 1943 where Stalin would focus more on talent, than loyalty. But in the early phase of the war in the east, this was invaluable to Stalin. With the armed forces behind him, his ability to arrest and terrorise his citizens to maintain his control – the conditions did not match those of World War I. Stalin’s grip on power was more absolute and he was definitely not willing to relinquish control.

Stalingrad was a catalyst for Soviet resistance and invaluable as a source of propaganda. The willingness of Soviet forces to resist the Germans, culminating in their encirclement and surrender, solidified the ‘heart’ of the country. The suffering at Leningrad and Moscow was justified -if- Soviet forces could turn the tide of the war. And they did.

Overy, R. Why the Allies Won
‘The drive to succeed in the battles in 1943 stemmed from violent emotions and a directed hatred. The stubbornness of Soviet resistance astonished German commanders; the ferocity of the confrontation led to barbarisms on both sides. The contest came to assume the character of that very struggle of nature which Hitler believed lay at the root of all human life, the survival of the fittest. The Soviet will to win, which emerged painfully from the wreckage of Soviet fortunes before Stalingrad, was not a mere abstraction but a spur to efforts that both sides, Soviet and German, would have thought impossible a year before. The Soviet people were the instrument of their own redemption from the depths of war.’

A few last thoughts…

The initial attack on the Soviet Union was ultimately successful because Stalin could not believe that Hitler would attack, and ignored reports that he had done so. By then, the damage was done, as the Germans poured across the front into Soviet territory. But Soviet resistance was limited at this point – the one thing that they needed was time. The bulk of Soviet industry had been moved behind the Ural Mountains, and with the support of US programs, they were swiftly able to increase their technological and military output. One million miles of telephone wire, 14 million pairs of boots and 363,000 trucks all helped the Red Army to fight with growing efficiency, as did radios and other technology which the Soviets were able to mimic and mass produce. When this occurred, and the Soviets rolled Germany back at battles such as Kursk, support grew quickly, and the threat to Stalin, and the collapse of the Soviet Union in 1941/1942 was gone.