Complex sentence: In times of emergencies, the Senate would declare that a dictator was required, and the current consuls would appoint a dictator, and this was the only decision that could not be vetoed by the Tribune of the Plebs.
Split into simpler sentences: In times of emergencies, the Senate would declare that a dictator was required, and the current consuls would appoint a dictator. This was the only decision that could not be vetoed by the Tribune of the Plebs.