Former Bush speechwriter, and now Washington Post columnist, Michael Gerson has some thoughts this week on the person who has been called “the most religious Democrat since Jimmy Carter.”

That would be Hillary Clinton.

Consider this:

During a question-and-answer session at Tufts University immediately after the 2004 election, Sen. Hillary Clinton identified the alienation of religious voters as one of the Democratic Party’s main problems. And the appeal she proposed was straightforward: “No one can read the New Testament of our Bible without recognizing that Jesus had a lot more to say about how we treat the poor than most of the issues that were talked about in this election.”

There was a stiff dose of political calculation in her remarks — but also a streak of sincere liberal Protestantism. As Clinton methodically consolidates her hold on the Democratic presidential nomination, Republicans are facing, in the words of her spiritual biographer Paul Kengor, “the most religious Democrat since Jimmy Carter.” And this introduces an unpredictable element into a wide-open election.

Republicans are accustomed to Democrats who are either frankly secular — Howard Dean once asserted, “My religion doesn’t inform my public policy” — or so uncomfortable with religious language that, were the sound on the television switched off, you’d think they were admitting a sexual vice instead of affirming their deepest beliefs.

Clinton is neither secular nor awkward about her faith. She cites her Methodist upbringing as a formative experience, with its emphasis on “preaching and practicing the social gospel.” As a teenager in 1962, she heard and met the Rev. Martin Luther King Jr. in Chicago — what would have been a profound experience for a spiritually alert youth — and was later politically radicalized by his assassination. The likely Democratic nominee participates regularly in small-group Bible studies and is familiar with the works of Reinhold Niebuhr, Paul Tillich and Dietrich Bonhoeffer — the theological heroes of mainline Protestantism (and of some stray Evangelicals like myself).

In a nation obsessed by the influence of religious conservatives, it is easy to forget that liberal Protestants were once the dominant cultural influence in America. Beginning in the early 20th century, the social gospel advanced swiftly through most American denominations. Progressive presidents such as Woodrow Wilson spoke in the cadences of this movement: “Christianity was just as much intended to save society as to save the individual, and there is a sense in which it is more important that it should save society.”

This high-minded theological liberalism had many successes. It opposed the harsh excesses of industrialization, embraced the civil rights movement, resisted the Vietnam War and led opposition to apartheid in South Africa. It also had debilitating weaknesses — a preference for democratic socialism, a soft spot for Marxist strongmen, a flitting fascination with trendy causes and a theological shallowness that caused millions to flee the pews.

As an heir to this religious tradition, Hillary Clinton combines two traits that seem contradictory but really aren’t — moralism and social liberalism.

As a moralist, she has been willing to work with conservatives on issues such as religious freedom in the workplace and highlighting the destructive impact of pop culture on children. She has joined congressional efforts against human trafficking and was an early supporter of public funds for faith-based social services. None of this indicates a privatized religious faith.

At the same time, as Kengor points out in his insightful book, “God and Hillary Clinton,” her defense of abortion rights has been strident, even radical. She has attacked pro-life people as enemies of “evidence,” “science” and “the Constitution.” And she has blamed pro-life “ideologues” for the prevalence of abortions because of their “silent war on contraception” — a remarkable accusation that Roman Catholic opposition to birth control is somehow responsible for abortion in America.

There are other provocative thoughts contained in the column, about how Hillary may play with Roman Catholic voters, and how her race might be affected if Rudy Giuliani becomes the GOP nominee.