Complex sentence: The decision to expatriate him was, however, taken by the military themselves, knowing full well that it violated the constitution; the military offered the justification that exiling Zelaya was done "to avoid mob violence".
Split into simpler sentences: The decision to expatriate him was, however, taken by the military themselves, knowing full well that it violated the constitution. The military offered the justification that exiling Zelaya was done "to avoid mob violence".