The Democratic Party and Catholics enjoyed a long and fruitful marriage in Massachusetts. These days the commitment is more frayed than any political union this side of John and Elizabeth Edwards. The marital conversation has not yet approached Who’s Afraid of Virginia Woolf? in its intensity, but it might be damaging the Democrats nonetheless.

There was a time when both Catholics and the Democrats were a minority in Massachusetts. For that and a host of other reasons, Catholics gravitated to the Democratic Party and, indeed, helped to make the Democrats the dominant power in the state.

My favorite tale in that regard is from 1948, the first time Democrats gained control of the state House of Representatives. Planned Parenthood placed a proposal to liberalize contraception laws on the ballot. That brought the Catholic Church into a full-out campaign not seen before or since. As John A. Farrell wrote in Tip O’Neill and the Democratic Century, “Any doubts about Catholic militancy were answered in October, when 80,000 Catholic youths paraded in Boston; a million of the faithful lined the streets to watch.” The birth control measure was defeated by 200,000 votes statewide.

Catholics and the Democratic Party had a symbiotic rise in the Commonwealth, but that relationship is now in disrepair, largely over abortion.Catholics and the Democratic Party had a symbiotic rise in the Commonwealth, but that relationship is now in disrepair, largely over abortion. Indeed, the stark divide on the issue prompted Cardinal Sean O’Malley in 2007 to state that the support of many Catholics for Democratic candidates “borders on scandal.”

Yet it is not so much a division on issues, but rather a contempt shown toward Catholics that costs the Democrats politically.

The recent special election for a US Senate seat featured a distressingly simplistic debate around abortion and an amendment Scott Brown once filed in the Legislature to exempt emergency room personnel with sincerely held religious objections from administering a contraceptive, even to a victim of rape. The amendment was voted down and the measure to provide timely emergency contraceptives was passed unanimously. When asked about the “conscience clause” issue during a radio interview, Democratic candidate Martha Coakley said, “The law says that people are allowed to have that [religious freedom]…. You can have religious freedom; you probably shouldn’t work in the emergency room.”

Given that nearly half of Massachusetts residents are Catholic, it is probable that some of them work in emergency rooms. Not to mention the Catholic hospitals that have been providing care to patients in the Commonwealth for decades. It would not be unreasonable for those emergency room employees (including men and women who have taken religious vows) and the patients they have helped to feel dismissed by Coakley’s remarks.

Or consider an occasion during the Democratic primary when Coakley and Congressman Michael Capuano interjected themselves into a dispute between another congressman and a bishop — not here, but in Rhode Island. Why would two candidates, presumably with their hands full battling it out in Massachusetts, get involved in a dispute between Rep. Patrick Kennedy and Bishop Thomas Tobin of Rhode Island over the bishop’s order that the pro-choice Kennedy not receive communion? The unpopularity of Catholic bishops (especially to Democratic primary voters) seems like a plausible rationale.

There is no good reason for a Democrat to cede Catholic concerns to a candidate like Scott Brown. Brown offered full-throated support for waterboarding, a position that puts him squarely at odds with the US Conference of Catholic Bishops, which has stated that torture violates human dignity and “can never be justified.” And despite agreeing with some regulation of abortions and winning the support of pro-life groups in 2010, Brown has supported Roe v. Wade since at least 2004.

But none of this is really about the bishops or official Vatican doctrine, since few American Catholics these days take their political cues from the church. It is about the 49 percent of Massachusetts residents who identify as Catholic — whether they attend mass or not. Polling in 2006 indicates that about 32 percent of Massachusetts Catholics attend mass weekly, 23 percent a few times a month, and 36 percent a few times a year, while 9 percent never attend. Yet the low-commitment adherents still identify as Catholic.

Perhaps more surprisingly, Boston College historian James O’Toole notes in a recent book on Catholicism in Boston that, in the wake of the clergy sexual abuse scandal, most Catholics did not abandon their church. “That they stayed with it, even amid the heartbreaking scandal, evinces a desire to remain faithful members of the church,” writes O’Toole. Many of these people agree with the Democrats and disagree with the Catholic hierarchy on the hot-button social issues. But there is still something that reacts to the contempt the Democratic Party — the historical political home of Catholics — seems to have toward the church.

Back in 1846 a congressional aspirant recognized that his vote total had suffered in a county where a rumor had circulated that the candidate was disrespectful of religion. He sought to beat back such talk, declaring that he does not believe “any man has the right thus to insult the feelings, and injure the morals, of the community in which he may live.”

Pretty smart politician, that Abe Lincoln.

Maurice Cunningham is an associate professor political science at the University of Massachusetts at Boston.