"You claimed that the Catechism supports your claim, but you cannot cite a reference because there isn't one."

Incorrect.  I have cited the Catechism.  I'll do so again.  See 2321:  "The prohibition of murder does not abrogate the right to render an unjust aggressor unable to inflict harm. Legitimate defense is a grave duty for whoever is responsible for the lives of others or the common good."

You say:  "You claim to be familiar with the Just War theory, but you don't seem to be aware that it is rooted in Natural Law reasoning, from pre- and extra-Christian sources, not in Scripture."

I quite aware that just war theory is rooted in Natural Law.  In fact, that's what I was alluding to when I said that Jesus' approval of the use of force in self-defense is supported by reason.  You yourself are see no rationality in NOT using force to defend the country, otherwise you'd accept what you THINK Jesus taught, and advocate disarming the country.  Stop posing.