The free translation of "Por la razón o la fuerza" loses the spirit of the phrase, a better translation of "razón" would be "reason", and a much better overall translation would be "By means of reason or force" or "By reason or force". Might implies some kind of status over the opponent, while the term "fuerza" must be interpreted as strenght or force of will, instead of a superior power.
So, though "By right or might" rhymes and sounds cool, a much better translation is "By reason or force".