Complex sentence: Democracies are instituted to ensure freedom for all and popular control over government authority; demagogues turn power deriving from popular support into a force that undermines the very freedoms and rule of law that democracies are made to protect.
Split into simpler sentences: Democracies are instituted to ensure freedom for all and popular control over government authority. Demagogues turn power deriving from popular support into a force that undermines the very freedoms and rule of law that democracies are made to protect.