How quickly we forget the lessons of Watergate and the Nixon White House.

Consider this: As a tense constitutional crisis loomed, Howard University's graduating class of 1974 heard a final lecture—a thundering civics lesson. That commencement speaker was Barbara Jordan of Houston, a 38-year-old member of Congress.

Two months later, on July 24, 1974, Jordan would step onto the world stage with her riveting televised remarks before the House Judiciary Committee. Revelations of the Nixon administration's secret abuses of power had stirred her to a spirited defense of the Constitution.

Jordan's message at Howard was a dramatic warning that Americans could "stand on the edge of repression and tyranny and never know it." The erosion of civil liberties, she declared, was not happening all at once, but one step at a time under the guise of law and order, national security and the invocation of executive privilege.

Tracing the historical advances of individual freedom, Jordan cited the principles of English Common Law, the Declaration of Independence and the Constitutional Convention. She quoted William Pitt's words on the right to privacy: "The poorest man may, in his cottage, bid defiance to all the forces of the Crown. ... The storm may enter, the rain may enter, but the King of England cannot enter."

She described the U.S. Constitution and the Bill of Rights as a balance between the government's interests and those of the governed, adding that the history of individual liberty in America has been one of popular resistance to government encroachment.

Although Thomas Jefferson had foreseen a natural tendency for liberty to yield and government to gain ground, Jordan recognized that modern technology had given new meaning to Jefferson's warning. "In addition to the continuing reality of smashed doors and actual physical invasion of private homes," she warned, "we know that government has more sophisticated and more invidious tools—electronic tools."

But it was not the new technology that alarmed Barbara Jordan; it was the Nixon administration's "shocking pattern of disregard for constitutional principles and due process of law." She cited threats to freedom of the press, politicization of federal investigative agencies and suspension of the Fourth Amendment protection against unreasonable searches and seizures in the name of national security. Dismissing the claim that the president has the authority to circumvent or suspend the Bill of Rights, she described government as "a potent, omnipresent teacher for good or ill." If the government becomes a law-breaker, she continued, "it breeds contempt for law and invites man to become a law in and of himself."

In several respects, today's erosion of civil liberties is even more ominous than the abuses of the Watergate era. Powerful new technological tools enable federal agencies to track millions of domestic telephone calls, written communications, medical and financial records.

At the same time, the current Bush administration's data-mining programs are shrouded in secrecy by a White House whose record of withholding information from the public and Congress is unprecedented. Anyone who alerts the public is branded as a traitor and threatened with subpoenas and prosecution.

The excesses of the Nixon White House ultimately could not withstand the scrutiny of the press, congressional oversight investigations and a unanimous Supreme Court ruling affirming that the president is not above the law. Yet, now two of these three constitutional checks and balances are either inoperative or ineffective in protecting the rights of American citizens.

Although Barbara Jordan may not have anticipated the magnitude of today's federal encroachments on individual liberties, she did anticipate their recurrence. "Freedom is the fluid, intangible condition of our society," she declared. "It thrives in some periods, and it is beset in other periods."

Her eloquent warning reminds us that the preservation of fundamental liberties requires the commitment of knowledgeable citizens, the respect of government and the vigilance of patriots.

Sherman is professor emeritus and former dean of the Lyndon B. Johnson School of Public Affairs at the University of Texas at Austin. He is editor of the forthcoming "Barbara Jordan: Speaking the Truth with Eloquent Thunder."