>>23470
>Their ideology propelled them to go forward and "liberate the proletariat" there. And they wouldn't stop there since their main targets were the western countries - they told so in their publications since the Great Revolution.

Stalin slowly downplayed the World Revolution thing, and in the end it was "we can build socialism in one country". Loss in Spanish war also put some skepticism in.

>More reason just to keep with Stalin Line to defend the country. It was also for slowing down enemy and give time to bring in reinforcement.

But overconfidence brings other reason - having defenses far from border means losing territory until glorious Red Army goes into liberating counterattack. Having forces near border means that no land would be given to invaders.

>Also this counter-attack part didn't exist in any heads. As you mentioned WWI was very fresh in the memories they didn't really know how a mobile warfare would play, so concentrating mechanized forces for a counter-attack and develop that into a breakthrough (and then develop that into deep battle) is a very alien thought

It is pretty complex question. Yes, WWI was in memory, and generals always prepare to previous war, but interwar times had pretty serious change in strategies. Especially with introduction of mass tank armies, that were synonym of mobile warfare. Would anyone invest in so much tanks if they had old-style trench warfare in mind?

>>23498
>They were boosted with mechanized corps with large amount of tanks (16 corps each with at least 1000 tanks) and motorized infantry. Mechanized corps are the main tool of punching a hole in the enemy lines.

Soviets thought that mechanization is the future, offensive or defensive, doesn't matter. Every operation has tactical and strategical offensives. Mechanized units are versatile, they are better overall than any pure-infantry ones. WWI legacy also influenced this - everyone remembered that lack of maneuverability was biggest problem, even successful breaching of enemy lines often resulted in nothing, because forces couldn't achieve success before enemy moved reserves. But now it could be fixed.