Nearly 50% of the Officer Corp....

...in the United States Military is Catholic.

From the Catechism of the Catholic Church (1997):

1909 Finally, the common good requires peace, that is, the stability and security of a just order. It presupposes that authority should ensure by morally acceptable means the security of society and its members. It is the basis of the right to legitimate personal and collective defense.

2239 It is the duty of citizens to contribute along with the civil authorities to the good of society in a spirit of truth, justice, solidarity, and freedom. The love and service of one's country follow from the duty of gratitude and belong to the order of charity. Submission to legitimate authorities and service of the common good require citizens to fulfill their roles in the life of the political community.

2310 ...Those who are sworn to serve their country in the armed forces are servants of the security and freedom of nations. If they carry out their duty honorably, they truly contribute to the common good of the nation and the maintenance of peace.