>>64187096
Paragraph 2309 of the Catechism outlines four conditions for the moral legitimacy of using military force for self-defense:
Lasting, grave, and certain damage: The harm inflicted by an aggressor on a nation or community must be of a serious and definite nature.
Last resort: All peaceful means for resolving the conflict must have been exhausted or proven ineffective.
Serious prospects of success: There must be a reasonable probability that military action will succeed.
Proportionality: The use of armed force must not create evils and disorders that are greater than the evil being eliminated. The power of modern weaponry is a heavy factor in evaluating this condition.
I am Protestant but am aware of the lack of many theologically sound writings that are ignored by our many denominations.
God bless.