JOEL - One of our Articles of Faith(#12) says the following:
"We believe in being subject to kings, presidents, rulers, and magistrates, in obeying, honoring, and sustaining the law."

Gennerally speaking we renounce war and proclaim peace(D&C 98:16). We are followers of our Redeemer, the Lord Jesus Christ, who was the Prince of Peace. But if we are called upon to defend our country then we support that call and serve our country the best we can in whatever branch of the military we are in; regardless of whether we are drafted or sign up voluntarily.
Our scriptures tell us that there are times and circumstances when nations are justified, in fact have an obligation, to fight for family, for liberty, and against tyranny, threat, and oppression(Alma 46).
Those in the Church who serve in the military are treated by other Church members with respect and gratitude for their choice to serve their country in this way.