Conflicting political visions, competitive jockeying and American dominance stand in the way of a more coordinated and efficient military machine.

Defending against an unpredictable Russia in years to come will mean bumping up against a strained social safety net and ambitious climate transition plans.

As the country’s leaders lay postwar plans, companies from around the world are jockeying for advantage in what could be a multibillion-dollar effort, although one...