The following is taken from Chapter 1 of Germany's War: The Origins, Aftermath and Atrocities of World War II by John Wear, published 2014, which can be read in full on The Unz Review or obtained on Amazon. You can read more of Wear's work at his website.
In this section, Wear describes how the Red Army was clearly in an offensive posture in 1941. The Soviets had discontinued production of defensive weapons like landmines, anti-tank weapons and flak guns. They had built up the transport infrastructure on their western border, a move that would only make sense if they intended to attack. Their commanders had been issued maps of the regions west of the Soviet border.
After having been captured by German troops, Stalin's son was asked about an unsent letter in his pocket referencing a "walk to Berlin," at which the Soviet prince muttered, "damn it."
After the division of Poland by the Soviet Union and Germany, Soviet troops could have created a powerful barrier on the new Soviet-German border. In 1939 conditions for defense along the Soviet-German border were highly favorable: forests, rivers, swamps, few roads, and lots of time. However, instead of making the area impassable, it was quickly made more penetrable. The Red Army tore down previously existing fortifications and buried them under mounds of ground. The Soviet Union also stopped producing anti-tank and anti-aircraft cannon. The Soviet Union had huge land mine production that could have been used for defense, but after the new borders with Germany were established this production was curbed.
The Red Army also dismantled the security pale created earlier on the old western borders, and failed to create a new security pale on the Polish territory annexed to the Soviet Union. The Red Army in Finland learned the hard way that a security pale could ease the position of the defense and complicate the position of the aggressor. All Soviet commanders expressed their awe at the Finnish line of defense. The Soviet Union had to expend a huge amount of time, strength, resources, and blood to cross the Finnish security pale. However, the Soviet Union dismantled its security pale in 1940 because it was not interested in conducting a defensive war.
The Soviet Union also constructed new railroads and railroad bridges in the western border regions. Almost all railroad troops were concentrated in the western border regions. The railroad troops worked intensively to modernize old railroads and build new ones right up to the border. Simultaneously with the construction of railroads, automobile roads were built in the western regions. The Red Army was building railroads and roads from east to west, which is usually done when preparing for advance, for a quick transfer of reserves, and for further supplying the troops after they crossed the borders. All of this work was designed for offense and hurt the Soviet Union in a defensive war. When Germany attacked the Soviet Union, German troops used the roads, bridges, supplies, rails, and sectional bridges constructed by the Soviets in the western regions to aid their advance into Soviet territory.
The Soviet Union also destroyed its partisan movement in the late 1930s. Soviet leaders knew that partisan tactics could win a war against any aggressor. With the largest territory of any country in the world, Soviet territory naturally facilitated partisan warfare. In the 1920s, Stalin created light mobile units and stationed them in the woods in the event of a German attack. These partisan units were comprised only of commanders, organizers, and specialists that acted as a nucleus. At the very beginning of a war, each peacetime partisan unit would expand into a powerful formation numbering thousands of people.
The Soviet peacetime partisan groups had secret bases created in impenetrable forests and islets amid the swamps. In an emergency, the partisans could easily disappear from any attackers into the mined forests and swamps, which were impassable to the enemy. Soviet partisan units were formed in the Soviet security pale, where during retreat of Soviet troops all bridges would be blown up, tunnels buried, and railroads and communication channels destroyed. The partisan groups were trained to prevent the enemy from restoring the destroyed infrastructure. In addition, some partisans were trained for undercover activities. These partisans did not retreat to the forests, but stayed in the cities and towns with the task of “gaining the trust of the enemy” and “offering him assistance.”
In the Soviet Union’s invasion of Finland, the Red Army encountered the Mannerheim Line, a security pale before it, and light squads of partisan fighters within. The light ski units of Finnish partisans carried out sudden strikes and then immediately disappeared into the forests. The Red Army suffered tremendous casualties from these strikes. All of the Red Army’s modern technology was useless in a fight against an enemy that evaded open battle.
However, having learned a cruel lesson in Finland, Stalin did not change his mind and create partisan units in the western regions of the Soviet Union. As the Soviet Union’s industrial and military might grew, Stalin planned to fight enemies on their soil rather than on Soviet land. In the second half of the 1930s, defense systems and partisan units became unnecessary for the Soviet Union. Stalin reestablished partisan units only after Germany had invaded the Soviet Union.
From 1926 to 1937, the Soviet Union constructed 13 fortified regions along its western borders known unofficially as “the Stalin Line.” There were many differences between the Soviet Stalin Line and the French Maginot Line. Unlike the French Maginot Line, the Stalin Line was built in secrecy and not publicized. The Stalin Line was much deeper and was built not only to stop infantry, but mostly to stop tanks. The Soviets also used huge quantities of steel and granite boulders in addition to concrete. The Stalin Line was built from the Baltic Sea in the north to the Black Sea in the south and could not be bypassed. Finally, unlike the Maginot Line, the Stalin Line was not built at the very border, but farther into Soviet territory.
The 13 fortified regions on the Stalin Line were built for defense and came at a tremendous cost in effort and money. Each fortified region was also a military formation that could independently conduct military operations during a long period of time and in isolated conditions. In 1938 it was decided to strengthen all 13 regions by building heavy artillery installations within them. The Soviet Union also started construction of eight more fortified regions. Then, when the MolotovRibbentrop Pact created a common border between Germany and the Soviet Union, Stalin ordered further construction of the fortified regions to stop. The existing fortified regions were disarmed, and everything connected with defense was dismantled and destroyed.
The construction of a new line of fortified regions began during the summer of 1940 on the new Soviet-German border. These new regions were unofficially referred to as the Molotov Line, but they were never finished. The defense buildup on the new borders proceeded very slowly, while the destruction of the Stalin Line was surprisingly fast. When Germany attacked the Soviet Union on June 22, 1941, the Molotov Line was not yet built. Soviet generals and marshals after Stalin’s death unanimously expressed their anger. They asked: How could Stalin liquidate and disarm the fortified regions on the old borders without building the necessary defenses on the new western borders? The answer is that Stalin was not planning to fight on his territory; Stalin was planning an offensive war against all of Europe.
Another defense system of the Soviet Union was the Dnepr military flotilla. All Dnepr river bridges were mined before 1939 and could be thoroughly demolished so that nothing would be left to restore. The Dnepr military flotilla was created in the early 1930s to prevent the establishment and crossing of temporary bridges across the river. The flotilla included 120 warships and motorboats, as well as its own air force with shoreline and air defense batteries. The Dnepr flotilla could securely close off the roads to the industrial regions in the south of Ukraine and to the Black Sea bases of the Soviet navy. A German attack could be stopped on the Dnepr line, or at least held up for several months. However, when Hitler attacked France, Stalin ordered the removal of mines from the Dnepr river bridges and disbanded the military flotilla. The Dnepr flotilla could only be used in a defensive war on Soviet territory, and Stalin did not believe he needed it.
Stalin divided the defensive Dnepr flotilla into two flotillas: the Danube flotilla and the Pinsk flotilla. The Danube flotilla would be useless in a defensive war. In an offensive war, however, the Danube flotilla could be deadly for Germany. It only had to sail 300 or 400 kilometers up the river to the strategically important bridge at Chernavoda, where it could disrupt the petroleum supply from Ploiesti to the port of Constanza. The entire German war machine could be stopped simply because German tanks, planes, and warships would be out of fuel. However, when Germany attacked the Soviet Union, the Danube flotilla found itself cut off from Soviet troops without the possibility of retreat. Most of its ships had to be sunk, while gigantic supplies were either destroyed or left behind.
The Pinsk flotilla would also be difficult to use for defense. The Pinsk flotilla had 66 river warships and cutters, a squadron of airplanes, a company of marines, and other units. In the defensive war of 1941, the Soviets had to blow up and abandon all of the ships of the Pinsk flotilla. However, in a war of aggression, the Pinsk flotilla could have used the newly constructed canal from Pinsk to Kobrin, which would then allow its ships to reach the Vistula basin and head further west to the German rivers. In 1945, a Soviet admiral reached Berlin with his flotilla. 
The records of a conference of the Soviet High Command held in Moscow from Dec. 23, 1940, through the evening of Dec. 31, 1940, also indicate that the Soviet Union was planning a massive offensive against Europe. This extremely secret meeting was attended by 274 of the highest-ranking leaders of the Red Army. Most of the speakers discussed the importance of the new tactics of sudden surprise attack. Defense at the primary locations of attack was not foreseen, even theoretically. The Soviet military leaders made it clear at the conference that they had no established contemporary defense theory. Soviet military leaders also did not work on questions of defense after the conference. The goal of the Red Army was to conduct grandiose, sudden, offensive operations that overwhelmed the enemy on its own territory.
During the German invasion of the Soviet Union in June 1941, Yakov Iosifovich Dzhugashvili, the son of Stalin, was taken prisoner by the Germans. Stalin’s son was searched and questioned. A letter dated June 11, 1941, was found in his pockets from another officer stating: “I am at the training camps. I would like to be home by fall, but the planned walk to Berlin might hinder this.” German intelligence officers asked Yakov Dzhugashvili to clarify the statement about the “planned walk to Berlin.” Stalin’s son read the letter and quietly muttered: “Damn it!” Obviously, the letter indicates that Soviet forces were planning to invade Germany later that year.
German intelligence officers also asked Stalin’s son why the Soviet artillery, which had the best cannon and howitzers in the world, fired so poorly. Stalin’s son truthfully answered: “The maps let the Red Army down, because the war, contrary to expectations, unfolded to the east of the state border.” The Soviet maps were of territories in which the Red Army planned to advance, and were useless for defending the country. Storages of topographic maps located unreasonably close to the border were either destroyed by the advancing German army or by the retreating Soviet forces. In 1941, the Red Army fought without maps, and the Soviet artillery could not fire accurately without maps.
Every Soviet commander, starting with regiment level and higher, had in his safe a so-called “Red Packet,” which contained the plans for war. When Germany invaded, the commanders opened their “Red Packets,” but they did not find in them anything useful for defense. The Red Army had neither prepared for defense nor conducted any training in defensive operations. The defensive operations of the Red Army in the summer of 1941 were pure improvisation.
The actions of the Red Army during the first days of the war speak best about Soviet intentions to conduct an offensive war. Up until June 30, 1941, Gen. Zhukov insisted on advance and demanded that commanders of Soviet forces aimed at Romania and Hungary exclusively attack. Zhukov stopped the attack only when he and his colleagues concluded that his armies could no longer advance. On June 22, 1941, several other Soviet commanders also followed prewar plans without awaiting orders from Moscow, and attacked the following regions: the Rava-Russkaya region, Tilzit in Eastern Prussia, and the Polish city of Suvalki.
The actions of the Soviet fleet during the first days of the war also show with sufficient clarity its plans for offense. On June 22, 1941, the submarines of the Baltic Fleet sailed toward the shores of Germany with the objective of sinking all enemy ships and vessels according to the rules of unrestricted warfare. No exceptions were made, not even for medical vessels sailing under the Red Cross flag. Soviet submarines from the Black Sea Fleet immediately sailed into the sea toward the shores of Romania, Bulgaria, and Turkey. On June 25 and 26, 1941, the Black Sea fleet’s cruisers carried out an intensive artillery raid in the vicinity of the Romanian port of Constanta. At the same time, the Danube military flotilla began an assault in the Danube river delta. The garrison of the Soviet naval base Hanko also conducted intensive assault operations during the beginning of the war, taking over 19 Finnish islands in the course of several days.
The Soviet air force also acted in an aggressive manner at the start of the war. On June 25, 1941, despite losses suffered during the first days of the war, Soviet air forces bombed all known air fields of the southern part of Finland. On June 23, 1941, acting according to plans, the Soviet long-range bomber air force carried out a massive attack against military targets in Koenigsberg and Danzig. Soviet long-range bombers also began to bomb the Ploiesti oil fields in Romania on June 26, 1941. After a few days of raids, the amount of oil Germany obtained in Romania was reduced almost in half. If Hitler had not attacked first, the Soviet air force would have been much more dangerous, and could have totally paralyzed the entire German war effort through its strikes against the oil-producing regions.
Further evidence that the Soviet Union was planning to attack Germany is provided by Andrei Vlasov, a Soviet general who had been captured by the Germans. During a conversation in 1942 with SS Gen. Richard Hildebrandt, Vlasov was asked if and when Stalin had intended to attack Germany. Hildebrandt later stated: “Vlasov responded by saying that the attack was planned for August-September 1941. The Russians had been preparing the attack since the beginning of the year, which took quite a while because of the poor Russian railroad network. Hitler had sized up the situation entirely correctly, and had struck directly into the Russian buildup. This, said Vlasov, is the reason for the tremendous initial German successes.”
Source: Unz Review