On May 10, 48 members of the U.S. House of Representatives --- all Catholics, all Democrats, 45 pro-choice, three pro-life --- wrote Cardinal Theodore McCarrick of Washington, chairman of the bishops' "Task Force on Catholic Bishops and Catholic Politicians." Their letter bespoke a host of confusions about the nature of the abortion issue, the responsibilities of legislators, and church law.

One confusion has to do with the public character of the abortion license, which the members described repeatedly as a matter of "personal morality." This is precisely wrong. Abortion, as the bishops have consistently taught, is a matter of the Fifth Commandment, not the Sixth; it's a question of public justice, not sexual morals.

Why? Because abortion involves taking the life of an indisputably human creature, endowed with an inalienable right to life. That is a serious public matter, not a private choice, because protecting innocent life is one of the first requirements of justice in any decent society.

Roe v. Wade (the 1973 Supreme Court decision that tried to justify abortion via an alleged "right to privacy") and Casey v. Planned Parenthood (the 1992 decision that re-tooled the abortion license as a "liberty right") were both wrongly decided --- just as Dred Scott v. Sandford, the 1857 decision declaring African-Americans legal non-persons, was wrongly decided.

As the pope, the Congregation for the Doctrine of the Faith, and the U.S. bishops have all taught --- and as any reputable theory of justice would confirm --- legislators who have sworn to uphold the rule of law, but who recognize that the Supreme Court has made a grave error, have certain responsibilities; they can't simply wash their hands of the affair, on the grounds that, well, the Court has settled the issue.

To begin with, legislators have an obligation to state publicly that the Court got it wrong. In their letter, the members justified pro-choice voting records on the grounds that "the Supreme Court has declared that our Constitution provides women with a right to an abortion." Anyone truly opposed to abortion would immediately continue, "But the Court, sadly, was wrong. Tragically and lethally wrong."

Secondly, conscientious legislators have a moral obligation to try to limit the damage caused by bad Supreme Court decisions. Some of the members who wrote Cardinal McCarrick have done so; most have not.

Moreover, few of the signatories have made any serious effort to change the dynamics within the Democratic Party, in which unabashed support for the abortion license is the litmus test for national office and the litmus test for weighing judicial nominees. This suggests that most of these members are not working, as any morally serious legislator must, to reverse the Court's wrongheaded abortion decisions --- which is the third requirement for lawmakers in situations like post-Roe v. Wade America.

The members also mistakenly invoke Jesuit Father John Courtney Murray in defense of their attempt to describe abortion as an issue of "private" morality not subject to legal regulation. Murray (who died almost six years before Roe) was dubious about the wisdom of the church defending state laws that criminalized the sale of contraceptives. But contraception, while a serious sin with grave cultural implications, is, in essence, a matter of conjugal morality and the Sixth Commandment; abortion is a matter of public justice and the Fifth Commandment. That's the distinction Murray would likely draw, not the one suggested by the Members.

Finally, the members misrepresent canon law and the purpose of canonical penalties. Canon 915 states that those who "obstinately persist in manifest grave sin are not to be admitted to Holy Communion." The application of this canon to present circumstances is being vigorously debated throughout the United States (and in Rome) right now.

The debate would be a wiser one if everyone understood (as the 48 members of Congress evidently do not) that canonical penalties have a different aim than penalties in civil and criminal law. The purpose of canonical penalties is remedial, even medicinal: imposing a penalty is intended, not so much as a punishment, but as a prod to conversion. The aim is not retribution, but change of heart and mind.

The members' letter did not, alas, advance an important debate. It muddied the waters even further.

George Weigel is a senior fellow of the Ethics and Public Policy Center in Washington, D.C.