The States are not a democracy. They are a democratic (all citizens) republic (government by proxy vote). See nitrogen''s reply.
A democracy would indeed find it easy to change such things as the TSA. Unfortunately a democracy would also find it easy to, say, change the rules of evidence governing proof of your guilt, because their perception of you is that you are bad and need to be punished, and the court system is one way to do that.
It is the tragedy of democracies that it is easy to make major decisions hastily whose consequences are either not understood well or understood all too well by a few for their own advantage.
Protecting minorities from being run over by the majority. Focusing on voting implies that two wolves and a sheep voting on what's for dinner made a democratic decision.
Protection of minorities include at least freedom of speech, freedom of assembly, property rights, the rule of law and strong, independent institutions to enforce these.
Voting is mostly useful for facilitating peaceful periodic transfers of power, as opposed to chaotic, even bloody, revolutions.
A democracy would indeed find it easy to change such things as the TSA. Unfortunately a democracy would also find it easy to, say, change the rules of evidence governing proof of your guilt, because their perception of you is that you are bad and need to be punished, and the court system is one way to do that.
It is the tragedy of democracies that it is easy to make major decisions hastily whose consequences are either not understood well or understood all too well by a few for their own advantage.