The only effective countermeasures against the foreign politics discussed earlier
“Of all the kings the Romans attacked, only Mithridates defended himself with courage and posed a threat to them.
Nothing had been more ruinous to most of the kings than their manifest desire for peace. This deterred all other peoples from sharing with them a peril from which they themselves wanted so much to escape. But Mithridates immediately let it be known to all that he was an enemy of the Romans and always would be.
Finally, the cities of Greece and Asia, feeling the yoke of the Romans weigh more heavily on them every day, placed their confidence in this barbarian king who summoned them to liberty.
Proscriptions, the practice of which began in those times, forced many Romans to leave their country. Mithridates welcomed them with open arms. He formed legions in which he enrolled them and which were his best troops.”
Montesquieu, Considerations on the Causes of the Greatness of the Romans and their Decline, 1734 (CHAPTER VII. HOW MITHRIDATES WAS ABLE TO RESIST THEM)