Sure, I skipped over that since the question was about China.
The reason he gave for Russia invading Ukraine is geographic. Over the course of its history Russia has been invaded fifty times, so they're touchy about that even if things look peaceful at the moment. Right now Russia has no real geographic boundaries, so it takes immense manpower to actually defend the borders, assuming you don't want to go nuclear. With the old Soviet borders, they had mountains and only nine passes to defend, which could be done relatively easily. Now they control one of those passes. Ukraine gives them two more plus a good base of operations to take the rest.
This fits his overall approach to geography: you want crunchy borders, good ports, and a productive interior with nice easy transportation inside. The US has all that in spades, a few other countries do to a lesser extent, most have various impediments, and all this drives a lot of everybody's history. His 2014 book applies this basic idea to many of the great civilizations in history, starting with ancient Egypt.
The reason he gave for Russia invading Ukraine is geographic. Over the course of its history Russia has been invaded fifty times, so they're touchy about that even if things look peaceful at the moment. Right now Russia has no real geographic boundaries, so it takes immense manpower to actually defend the borders, assuming you don't want to go nuclear. With the old Soviet borders, they had mountains and only nine passes to defend, which could be done relatively easily. Now they control one of those passes. Ukraine gives them two more plus a good base of operations to take the rest.
This fits his overall approach to geography: you want crunchy borders, good ports, and a productive interior with nice easy transportation inside. The US has all that in spades, a few other countries do to a lesser extent, most have various impediments, and all this drives a lot of everybody's history. His 2014 book applies this basic idea to many of the great civilizations in history, starting with ancient Egypt.