While violence and destruction is strongly discouraged in Buddhism, it is ok for a ruler or government of a country that adheres to Buddhist principles, to establish police and armed forces to:
- protect and guard the people
- ensure peace
- ensure that justice prevails
Please see Pali sutta quotes below.
However, what about the hypothetical case of Buddhists being persecuted in non-Buddhist lands? Buddhists in this case, should not bear arms and become freedom fighters or terrorists, as that is against the first precept and also other teachings e.g. removing mental aversion.
In this case, persecuted Buddhists should either leave the country (as what the 14th Dalai Lama had done in March 1959) or pursue peaceful legal means of action (as what Mahatma Gandhi or Martin Luther King had done) which could include petitions and letters to government officials and elected representatives, statements on media etc.
From DN 16:
"What have you heard, Ananda: do the Vajjis duly protect and guard the
arahats, so that those who have not come to the realm yet might do so,
and those who have already come might live there in peace?"
"I have heard, Lord, that they do."
"So long, Ananda, as this is the case, the growth of the Vajjis is to
be expected, not their decline."
From DN 26:
‘But sire, what are the noble duties of a wheel-turning monarch?’
‘Well then, my dear, relying only on principle—honoring, respecting,
and venerating principle, having principle as your flag, banner, and
authority — provide just protection and security for your court, troops,
aristocrats, vassals, brahmins and householders, people of town and
country, ascetics and brahmins, beasts and birds. Do not let injustice
prevail in the realm. Pay money to the penniless in the realm.