Complex sentence: Jack must stop a nuclear bomb from detonating in Los Angeles, then assist President David Palmer in proving who is responsible for the threat, in order to avoid an unfounded war between the United States and three innocent Middle Eastern countries.
Split into simpler sentences: Jack must stop a nuclear bomb from detonating in Los Angeles, then assist President David Palmer in proving who is responsible for the threat. This is necessary to avoid an unfounded war between the United States and three Middle Eastern countries.