In an unprovoked attack, terrorists shattered the American ethos of national security.

As we consider expanding the government's investigative authority, we must do so in a reasoned, careful and democratic fashion, relying on the very constitutional structure that those powers are designed to protect.

In an instant, the Twin Towers vanished from the New York skyline, and a section of the Pentagon was reduced to a smoldering mound of rubble.

The means of destruction, the terrorist's weapon of choice, was civilian aircraft. America's sense of safety was in a moment inalterably uprooted.

One of the most frightening elements of the Sept. 11 terrorist attacks is the anecdotal evidence now emerging from the federal investigation and news accounts that the perpetrators of these heinous crimes moved freely through our society without arousing suspicion from ordinary citizens or detection by law enforcement.

In doing so, they took advantage of the freedoms all of us enjoy, including the freedoms to live in an open society and to pursue individual goals and aspirations without interference or obstruction by the government.

This is about to change. In the aftermath of the attacks, the Bush administration and Congress are examining ways to recalibrate the existing balance between national security and individual liberties. It is a necessary process.

With appropriate oversight, our security agencies can and should be given the latitude necessary to prevent terrorist activity and find the terrorists operating in our midst.

While we must proceed wisely and deliberately, we can protect ourselves and root out evil without sacrificing the essence of what makes us a great nation and a free society. Any recalibration of civil rights vis-a-vis law enforcement power must start with the recognition that this country stands for a core set of ideals of individual liberty and freedoms.

Today there can be no doubt that our nation's security agencies need broader authority to pursue those individuals who would undermine our democratic way of life. The threat is very real. The terrorists who committed the attacks in New York and Washington, D.C., and Pennsylvania moved freely within our borders. They communicated using cellular phones, computers and the Internet and made ready use of technology to achieve their aims. They rented cars and applied for drivers' licenses.

Several of the terrorists rented homes in suburban communities, which turned out to be ideal hiding places and the staging grounds for terrorism.

How can law enforcement combat this new threat without overreaching constitutional boundaries?

First and foremost, we must provide the means to detect and foil illegal activities, cyber-terrorism and terror plots.

We must increase state and federal law enforcement powers to investigate domestic terrorist groups that knowingly support foreign terrorist entities.

President George W. Bush's executive order on terrorists' financing will give the federal government the ability to block and seize financial assets of terrorists and their supporters.

The government also should expand economic sanctions against state sponsors of terrorism.

The concern, of course, is the effect these changes and others could have on individual civil rights and liberties. We must strike an appropriate balance. Just as freedom of the press may be curtailed in times of war, or the right to be free from unreasonable searches may be rescinded with a showing of probable cause, limits on individual rights in this new all-out war against terrorism must be subject to judicial review.

In expanding the authority of law enforcement to "get the man," we must also invest our legal system with the authority to preside over the process to ensure that civil rights are protected.

Even when faced with the significant threat of international terrorism, law enforcement officials must never engage in inappropriate stereotyping or discriminatory profiling on the basis of ethnicity or religion. Members of specific ethnic or religious groups should not be singled out for different treatment on the basis of their individual characteristics. Suspicions must be grounded in factual evidence -- and again, the courts must be responsible for evaluating that evidence.

Expanded police powers should be checked by another source as well: the deliberative, accountable and democratic legislative process. Congress should carefully consider the implications of the range of new counterterrorism initiatives that will be offered. The political process, like the judicial one, can serve as an essential check on executive police powers.

Also of concern are hate crimes. As we move through this time of terrible tragedy, we must ensure that no one is singled out for hatred, prejudice or blame based on their ethnicity or religion.

Hate-motivated violence must be forcefully condemned and vigorously investigated and prosecuted as hate crimes. Muslims and Arab Americans must not be tainted by the deadly acts committed by a minority bent on destroying the American way of life.

We are at a precarious time in our nation's history. We will not abandon our rights out of false fears, but we will also not forget the harsh reality of Sept. 11: Terrorists do not play by our rules. Given the ability, they will exploit the democratic freedoms we all enjoy to carry out terrorist acts.

As we consider expanding the government's investigative authority, we must do so in a reasoned, careful and democratic fashion, relying on the constitutional structure that those powers are designed to protect.