Judge Andrew P. Napolitano is a senior judicial analyst at FNC. He appears regularly on The Big Story With John Gibson, Fox and Friends and The O'Reilly Factor.

Imagine the following scenario. You emigrated to the United States from a Third World country as a teenager and worked your way through school. Your wife and children were born here. You have a small business and a green card good for life. You have never broken the law.

One day, the local police change the traffic laws and you can't drive your car to your business any longer. You have been kicked off an airplane flight because the local police are allowing some passengers to vote to exclude others on the basis of race.

You must avoid talking to the federal police at all costs because one unacceptable or refused answer and you can be deported without charges, without trial, without judicial review, without ever seeing your family again, and without settling your business. You've learned that the federal police are looking for people who have similar facial features and ethnic backgrounds to yours, and have been holding them in secret jails without presenting evidence or giving them access to the courts.

What's going on here? This is New York City, 2002.

The laws were supposed to be fair and liberty guaranteed, but some politically powerful people want your liberty to be sacrificed for their safety. It wasn't supposed to be this way.

When Benjamin Franklin wrote, "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety," he could not have even contemplated the pain and fear facing many innocent people here today. But Franklin's argument — that in a democracy, personal freedom is a greater good than personal safety — while articulated 30 years before our Constitution was enacted, is the very essence of the Constitution itself. The Constitution, of course, was written not to grant liberty, but rather to restrain the government from interfering with it.

The U.S. Supreme Court has ruled that the rights actually articulated in the Constitution presume the existence of other, unarticulated rights such as freedom of thought, the right to privacy, and freedom to travel. Moreover, the Court has ruled, not only are the states and the federal government prohibited from interfering with those rights, but they must actually protect our exercise of them.

Now we are confronted with the arguments of those who ask why can't the FBI just break down the doors of suspected terrorists, why can't the police just stop and search suspicious-looking people on the streets, why can't we just lock up or deport the people who threaten us? After all, they assert, what good are freedoms if we lack the security — to use Franklin's word, "safety" — within which to exercise them?

Until 1776, our government didn't recognize personal liberties; but the Declaration of Independence, from which the violence of 1776 sprang, did. It asserted that our personal freedoms are our birthright, not dependent for existence on the beneficence of the government or even the will of the majority. Thus, the theory of the Declaration has been that the rights enumerated in the Constitution are natural, that is, they belong to all persons by virtue of our humanity. The theory of the Constitution, which recognizes natural rights and actually codifies many of them, is that the government cannot take away those rights without filing charges and holding a fair trial before a neutral jury.

The Constitution requires probable cause — specific reasons to persuade a judge that a specific person more likely than not committed a specific crime — before the government can arrest anyone. Without the requirement of probable cause, the government becomes a monster: Whom will it incarcerate or deport? Mexican busboys who look like Arabs, Middle Eastern chemical engineering students who don't wear American flags, political radicals who hate all wars?

The same logic used to justify stopping and searching, breaking and entering, interrogating and arresting someone who is dark-skinned and bearded today can be used against someone who is light-skinned and clean-shaven tomorrow.

Arguably, every major war the United States ever fought was against governments that wanted and claimed the power to knock down doors at night, stop people arbitrarily in the streets, and incarcerate them without due process. We won those wars and defeated those ideas.

What is the value of security if the freedoms within it are subject to the government's unchecked will? What freedoms are we defending if, in the name if freedom, the government can take them away because of a person's appearance or nationality? Who will decide — and under what standards — whose freedom stays and whose freedom goes?

Personal liberties in a free society are rarely diminished overnight. Rather, they are lost gradually, by the acts of well-meaning people, with good intentions, amid public approval. But the subtle loss of freedom is never recognized until the crisis is over and we look back in horror. And then it is too late.