That is not the definition of democracy; but, our Constitution divided power into as many parts as possible to prevent any group from imposing its will on others (including the majority): separation of powers (branches), federalism, different terms of office, different method of selection, different constituency, checks and balances....
In a direct democracy the people have the power to make the decisions. If a majority want to put all the power in one person that was the democratic decision. If the system prevents the people from making that decision that is why our system is not a democracy but a democratic republic or a constitutional republic that has evolved into a more democratic system.