Michael H. McCarthy recalls that over the past few years, when he told friends and colleagues that he was taking part in a project on lobbying ethics, they usually laughed or looked at him quizzically.

To many of them, the very notion of lobbying ethics seemed "either an oxymoron or the description of a quixotic task," said McCarthy, a philosophy professor at Vassar College who was part of a research team at the Woodstock Theological Center at Georgetown University in Washington.

The Woodstock team certainly didn't write off this fast-changing institution as beyond ethical reach. The Jesuit-sponsored center has issued a book titled "The Ethics of Lobbying: Organized Interests, Political Power, and the Common Good," newly published by Georgetown University Press after four years of study involving scores of prominent lobbyists together with ethicists and policy makers.

Included in the 110-page book are the "Woodstock Principles for the Ethical Conduct of Lobbying," a first-of-its-kind set of guidelines for all those involved in the process.

The skepticism that McCarthy encountered was real enough, though the popular images of corrupt lobbyists are mostly outdated. Few lobbyists today use bribery and other illegal tactics of the trade, but they do have highly sophisticated ways of manipulating public policy on behalf of private interests, often out of public view.

For example, the pharmaceutical industry reportedly has 636 paid lobbyists in Washington: more than one for every member of Congress. It spends $180 million a year on lobbying.

One item in the Woodstock Principles is directed at a particular kind of lobbying campaign that the industry has perfected. Under the heading of candid disclosure, the document states that lobbyists should have no part in "front organizations" that conceal the true identity of their clients.

Many critics complain that the pharmaceutical industry finances so-called grassroots organizations with names like "United Seniors Association." These groups oppose initiatives to extend Medicare coverage to prescription drugs and otherwise control drug costs. People who see their television commercials usually have no idea the industry is behind the multi-million-dollar ad campaigns.

The Woodstock Principles also tackle bigger questions. One has to do with a concept that Catholic theologians have talked about for centuries - the "common good." The first principle states: "The pursuit of lobbying must take into account the common good, not merely a particular client's interests narrowly considered."

That may seem reasonable enough to those steeped in the Catholic tradition, but the proposition has already set off fireworks in Washington.

"Unfortunately, I am afraid that I have trouble with the concept that there is an immutable common good that provides a measurable guidepost for lobbying activity," said Thomas Susman, a prominent lawyer-lobbyist.

Susman subscribes to most of the Woodstock Principles but draws the line at the common good -- which, in Catholic teaching, includes special attention to the needs of the poor and vulnerable.

"The Ten Commandments - our most important and revered ethical code - say nothing about the disadvantaged and vulnerable. I question whether a lobbyists' code should."

These remarks, during a recent forum at Georgetown, did not surprise McCarthy. He and other facilitators spent many hours in conversation with high-powered Washington lobbyists. Whenever the question came up, the response typically was, "Who knows what the common good is?"

McCarthy had a direct response to that skepticism.

"The common good is what we are properly seeking to discover through public deliberation and argument. In its general outlines, it's already known in advance, but in its needed concreteness, especially as it bears on policy making and law, it is still to be discovered through practical inquiry and informed debate."

McCarthy and others argue that a commitment to the common good is no luxury in a sound democracy. Without it, politics is ruled by special interest - rather than a special concern for the weak and vulnerable.

Some lobbyists may be agnostic on this question, but that is not fazing the Woodstock Jesuits. Father Edward B. Arroyo, S.J., who coordinated the lobbying project, said he wants to get copies of the document in as many hands as possible, particularly in the nation's capital.

As for the next phase of this project, Father Arroyo has already settled upon a theme - the common good.

William Bole is a fellow of the Woodstock Theological Center at Georgetown University in Washington, and a journalist in Massachusetts. (To order a copy of "The Ethics of Lobbying," call 202-687-3532 or send an email to woodstock@georgetown.edu.)