Your Favorite Roman Latin Quotes Maxims Mottos Sayings ?

[Salvianus]

"Si vis pacem, para bellum." or
"Qui Desiderat Pacem Praeparet Bellum."

Translates as "If you want peace, prepare for war."

Attributed to Publius Flavius Vegetius Renatus, from or based on his "Epitoma rei militaris," possibly written around 390 AD.

Quite right: the latter is the phrase that appears directly in the introduction to Book III of Vegetius and I think is literally:"Let (one) who desires peace prepare for war"

Related to this, on peoples' right to self-defense and self-determination, I still struggle between approaches

I certainly share this particular dilemma! I suspect we will be off topic, if not outside the Forum Rules to pursue it here, but I will PM you

One germane Latin quote, very much on topic:
Vix ulla tam iniqua pax, quin bello vel aequissimo sit potior – "Scarcely is there any peace so unjust that it is not better than even the fairest war" (Erasmus)

and a motto:
fortiter in re, suaviter in modo
boldly in deed, gently in manner