So if Stalin was planning on sticking to their non-aggression pact, why did Hitler find it necessary to invade?
You aren't seeing the big picture. Some of what buchanan says isn't wrong, per se, its just way ing off-base. There are reasons Hitler didn't find it necessary to have a huge or dominant navy, for example. It would have been impossible to allocate the natural resources necessary, for starters. Additionally, you really think England or France or even America would have let him rule the seas? That was the most important power to have before Hitler shattered all those rules and focused instead on creating a huge air force.
Or how about why only two-engine bombers that had short flight distances? Do you forget what blitzkrieg is exactly? The plan was never to fight a war of attrition, it was to move so quickly while cutting off supply lines that no one knew what hit them. And it was in 1936 that rearmament went into full swing - and Nazi scientists did not have the necessary technology for efficient 4 engine bombers at this time, but had already designed some of the best fighters and bombers of the war with 1/2 engines.