Complex sentence: In turn, the United States used this incident as an excuse to exercise its prerogative under Article 35 of the Mallarino-Bidlack Agreement to safeguard the neutrality and free transit in Panama, and use of armed forces when the local government is deemed unfit.
Split into simpler sentences: In turn, the United States used this incident as an excuse to put Article 35 of the Mallarino-Bidlack Agreement into practice. That is to say, its prerogative of safeguarding the neutrality and free transit in Panama, and use of armed forces when the local government is deemed unfit.