I CONFESS. I am Roman Catholic in religion and liberal in politics. For years, I have been told by people on both sides of the political spectrum that this is a contradiction. Liberal acquaintances--especially at Harvard--who know my political leanings cannot fathom why I associate myself with the church of Peninsula, John Cardinal O'Connor, fanatical anti-abortionists, the Index of Banned Books and the Spanish Inquisition. They question my credentials as a liberal free thinker and, quite often, as an intelligent person.

When I was young, I never encountered this prejudice against. Catholics. For me, Catholic politics meant Democrats and the Kennedy clan, hardly conservatives. In fact, the most impressive moment of my childhood was when Father Ken, a parish priest with tangled hair and a long beard that made him look like a hippie, gave a sermon on the 1980 New York City march for peace.

He spoke in favor of nuclear disarmament, even a unilateral freeze. An old man in the congregation stood up and challenged his position, and the two proceeded to debate the peace movement. The old man yelled and screamed about defense and deterrents. Like a true peacemaker, Father Ken never raised his voice as he spoke of the evils of annihilation. When the old man lost the argument and stormed out of the church, the people in the congregation applauded in support of Father Ken and peace.

ADMITTEDLY, my parish at home is particularly liberal (almost as liberal as St. Paul's here at Harvard). In elementary school religion classes, we were taught that Jesus loved the poor more than the rich. We once visited a local synagogue to learn about how "our Jewish brothers and sisters" worship God. In our high school religious education program we discussed such issues as Christian social justice, being gay and Catholic and rock music and Christianity.

And I do not think that my experience is atypical of American Catholics. After all, Catholic social teaching shares much of the Democratic party's platform: opposition to the death penalty, runaway defense spending, apartheid in South Africa and military support for right-wing regimes in Latin America; support for federal and state welfare, prenatal care, gun control and educational spending. Despite the stereotype of conservative rank-and-file Catholics, the American Church's leadership, the American Council of Catholic Bishops, has taken high-profile stands against the arms race, homelessness and laissez-faire economics.

The unequivocal stance of the Gospel and the Church on social justice perhaps explains why so many prominent Catholic politicians such as N.Y. Gov. Mario Cuomo, Geraldine Ferraro and the Kennedys are so liberal.

In my own experience with the Church, I have found many role models for my moral and political convictions. I admire people like Archbishop Romero of El Salvador, the four American Maryknoll missionaries and six Jesuit priests who were martyred by rightwing terrorists because they dared to speak out for the poor. I look to people like the Epiphany Plowshares, a group of laypersons and clergy who were imprisoned for breaking into a missile assembly plant in Pennsylvania during an anti-war protest. Or a person like Mother Theresa of Calcutta, who devoted her life to helping the poorest of the poor in India, regardless of race, religion or creed.

THE Catholic Church is not an ideally liberal institution. Its historic treatment of women, homosexuals, Jews and heretic Christians, among others, has been quite appalling. Although the Church is truly universal in that it includes members from all races and on all continents, its Roman hierarchy is still dominated by white, European men. Its views on human sexuality, feminism, birth control and the family are often extremely conservative--perhaps unrealistically so. All too often, the most vociferous conservative voices in the institution choose only these issues as the focal points of their moral crusades.

What many non-Catholic and Catholic Americans alike fail to understand is the nature of a non-democratic institution such as the Church. Change is much slower in such a body; it simply cannot react to social change as fast as a democratic legislature can, so Americans often find its apparent resistance to reform to be completely alien. However, the institution does evolve to meet the demands of its people and is constantly in a process of gradual reform.

The Church in which I was raised was far different from the Church of my mother. In its liturgy, its emphasis on forgiveness instead of damnation, and its relative openness to involvement of lay members, today's Catholic Church has made tremendous strides in the past 25 years. In my lifetime, I expect ot see a similar renewal of the Church as it faces a whole new set of challenges presented by the changes of the 21st century.

I readily admit that I am not the best Catholic or the best liberal. I am very human; thus I am often very wrong. Likewise, the institution of the church has made many mistakes through the centuries. But as the Bible makes clear, any human institution is imperfect because of the weaknesses of people, not of the faith behind it.

The Church is not a liberal church, or even a church of liberals. It represents a broad spectrum of political beliefs united by a common faith--a faith that largely coincides with the underlying moral precepts of the politics of humanitarianism. The moral imperatives of the Church find political expression in groups as diverse as West European Christian Democrats and Latin American revolutionaries.

Politically, the Catholic Church is truly catholic. The existence of Catholics like Archbishop Bernard Law does not make me a conservative any more than the existence of Catholic "liberation theology" makes me a revolutionary. One can be a Catholic and remain a free thinker.