When the CCC says "For this reason,** those who legitimately hold authority **also have the right to use arms to repel aggressors against the civil community entrusted to their responsibility. "… we can know it refers to those appointed public officials… those ‘ordained’ in the public domain to protect the common good.
First of all, the term ‘legitimate’ has a specific canonical meaning. There is a legio, or law that grants ‘legtimatcy’, that is by definition of the word ‘legitimate’.
So the question then becomes, which law grants legitimacy. Civil law, in which case, gun owners ARE legitimate authorities. The legio, or law, has granted legitimacy
That also follows the function of civil law, which derives it’s authority from the people. The people could not grant the police or the military any right to bear arms if the people themselves do not have that right. You cannot grant what you do not have.
Now the people can choose to FORGO their right to bear arms, but the very fact that they granted that right to the police and to the military shows that they have that right to grant.
If you are referring to the Natural Law as granting legitimacy, being the ‘legio’ then the right of self defense is not limited to just the police and military. All have that right
Very soon to be St. Pope John Paul II stated so in the very Encyclical on the Right to Life, Evangelicum Vitae, para 55
legitimate defense can be not only a right but a grave duty for someone responsible for another’s life, the common good of the family or of the State". Unfortunately it happens that the need to render the aggressor incapable of causing harm sometimes involves taking his life. In this case, the fatal outcome is attributable to the aggressor whose action brought it about, even though he may not be morally responsible because of a lack of the use of reason
Note that the Pope specifies WHO has the right and the duty of defense. It is not just the good of the State represented by the police, but anyone who is responsible for a family, or for the life of another.
As a further question for you, consider the Jews in the Warsaw Ghetto Uprising of 1943
Do you consider that to be a legitimate defense, as outlined by Pope John Paul II above. If so, where did they get legitimacy, what ‘legio’ or law granted them the right to bear arms to defend themselves. It certainly was NOT the Civil Law; that prohibited Jews, and most other civilians of any type, from bearing arms.
That leaves only the Natural Law as the legio. And the Natural Law, by definition, applies to all humans everywhere.
The third alternative is that the Jews in the Warsaw Ghetto acted unjustly in bearing arms.
So which of those three do you hold to? That their legitimacy came from Civil Law, Natural Law or was an Injustice?