Usage patterns
国防を強化するto strengthen national defense
The government announced a policy to strengthen national defense.
国防に努めるto work toward national defense
The Self-Defense Forces work to maintain national defense.
国防上の〈事〉for reasons of national defense; from a national-defense standpoint
This information is not disclosed for national-defense reasons.
国防費を増やすto increase the defense budget
Many countries are increasing their defense budgets.