The Washington Post's recent series on Dick Cheney's vice presidency certainly got my attention. Having held that office myself over a quarter-century ago, I have more than a passing interest in its evolution from the backwater of American politics to the second most powerful position in our government. Almost all of that evolution, under presidents and vice presidents of both parties, has been positive — until now. Under George W. Bush and Dick Cheney, it has gone seriously off track.

The Founders created the vice presidency as a constitutional afterthought, solely to provide a president-in-reserve should the need arise. The only duty they specified was that the vice president should preside over the Senate. The office languished in obscurity and irrelevance for more than 150 years until Richard Nixon saw it as a platform from which to seek the Republican presidential nomination in 1960. That worked, and the office has been an effective launching pad for aspiring candidates since.

But it wasn't until Jimmy Carter assumed the presidency that the vice presidency took on a substantive role. Carter saw the office as an underused asset and set out to make the most of it. He gave me an office in the West Wing, unimpeded access to him and to the flow of information, and specific assignments at home and abroad. He asked me, as the only other nationally elected official, to be his adviser and partner on a range of issues.

Our relationship depended on trust, mutual respect and an acknowledgement that there was only one agenda to be served — the president's. Every Monday the two of us met privately for lunch; we could, and did, talk candidly about virtually anything. By the end of four years we had completed the "executivization" of the vice presidency, ending two centuries of confusion, derision and irrelevance surrounding the office.

Subsequent administrations followed this pattern. George H.W. Bush, Dan Quayle and Al Gore built their vice presidencies after this model, allowing for their different interests, experiences and capabilities as well as the needs of the presidents they served.

This all changed in 2001, and especially after Sept. 11, when Cheney set out to create a largely independent power center in the office of the vice president. His was an unprecedented attempt not only to shape administration policy but, alarmingly, to limit the policy options sent to the president. It is essential that a president know all the relevant facts and viable options before making decisions, yet Cheney has discarded the "honest broker" role he played as President Gerald Ford's chief of staff.

Through his vast government experience, through the friends he had been able to place in key positions and through his considerable political skills, he has been increasingly able to determine the answers to questions put to the president — because he has been able to determine the questions. It was Cheney who persuaded President Bush to sign an order that denied access to any court by foreign terrorism suspects and Cheney who determined that the Geneva Conventions did not apply to enemy combatants captured in Afghanistan and Iraq.

Rather than subject his views to an established (and rational) vetting process, his practice has been to trust only his immediate staff before taking ideas directly to the president. Many of the ideas that Bush has subsequently bought into have proved offensive to the values of the Constitution and have been embarrassingly overturned by the courts.

The corollary to Cheney's zealous embrace of secrecy is his near total aversion to the notion of accountability. I've never seen a former member of the House of Representatives demonstrate such contempt for Congress — even when it was controlled by his own party. His insistence on invoking executive privilege to block virtually every congressional request for information has been stupefying — it's almost as if he denies the legitimacy of an equal branch of government. Nor does he exhibit much respect for public opinion, which amounts to indifference toward being held accountable by the people who elected him.

Whatever authority a vice president has is derived from the president under whom he serves. There are NO powers inherent in the office; they must be delegated by the president. Somehow, not only has Cheney been given vast authority by President Bush — including, apparently, the entire intelligence portfolio — but he also pursues his own agenda. The real question is why the president allows this to happen.

Three decades ago we lived through another painful example of a White House exceeding its authority, lying to the American people, breaking the law and shrouding everything it did in secrecy.

Watergate wrenched the country, and our constitutional system, like nothing before. We spent years trying to identify and absorb the lessons of this great excess. But here we are again.

Since the Carter administration left office, we have been criticized for many things. Yet I remain enormously proud of what we did in those four years, especially that we told the truth, obeyed the law and kept the peace.

Walter F. Mondale was vice president of the United States from 1977 to 1981. He wrote this commentary for The Washington Post.