Last December, Rep. David Obey, a 25-year House member, received a letter from his Catholic Bishop, Raymond Burke of La Crosse, Wisconsin, stating that he should no longer present himself for communion.

In a public statement Burke said: Catholic legislators "who are members of the faithful of the diocese...and who continue to support procured abortion or euthanasia may not present themselves to receive holy Communion."

Further: "They are not to be admitted to holy Communion should they present themselves, until such time as they publicly renounce their support of these most unjust practices."

Rep. Obey was outraged: "Bishop Burke has a right to instruct me on matters of faith and morals in my private life and ? like any other citizen ? to try by persuasion, not dictation, to affect my vote on any public matter.

"But when he attempts to use his ecclesiastical position to dictate to American public officials how the power of law should be brought to bear against Americans who do not necessarily share our religious beliefs, on abortion or any other public issue, he crosses the line into unacceptable territory," he told The National Catholic Reporter.

"The US Constitution, which I have taken a sacred oath to defend, is designed to protect American citizens from just such authoritarian demands."

That stinging response had no impact on Burke, who was promoted to Archbishop of St. Louis. On February 1, he told reporters that if Sen. John Kerry, a candidate in the Missouri presidential primary, approached him for Communion: "I would have to admonish him not to present himself for Communion."

Ironically, Obey's record on abortion is far more moderate than that of Kerry. Obey supported the ban on "partial birth abortion".

According to Carol Tobias of National Right to Life: "John Kerry is the most aggressively radical pro-abortion candidate that has ever run for President. In his announcement speech, he said he would only nominate judges that support abortion."

On the other hand, Kerry will be the first Catholic to be nominated for president since John Kennedy. He knows how important the Catholic vote is in presidential elections. And it is a swing vote.

Catholics put John Kennedy in the White House, winning 83 percent of their vote in a race that Kennedy edged Nixon by only 100,000 votes.

However, a majority of Catholics voted for Nixon in 1972 and Ronald Reagan won 15 million Catholic votes. But Catholics help put Jimmy Carter and Bill Clinton in the White House.

On the other hand, the percentage of Catholics who call themselves "Democrats" has fallen from 67 to 41 percent.

Therefore, the attitude of Catholic bishops toward militant pro-abortion candidates like Kerry is important. Generally, Catholic bishops have refrained from partisan politics.

Instead, they have articulated their positions on substantive issues, some of which favour Democratic candidates: opposition to the Iraqi war and support of programmes to aid the poor and the environment.

Their opposition to abortion, euthanasia and same-sex marriage supports Republican candidates.

However, some Catholic bishops are becoming more militant on abortion. The day before his installation as Archbishop of Boston, Sean O'Malley announced: "A Catholic politician who holds a public, pro-choice position should not be receiving Communion and should on their own volition, refrain from doing so."

But he would not "deny Communion" to anyone.

In Rome Cardinal Francis Arinze made headlines recently when he said that Catholic politicians who were unambiguously pro-abortion should not be given Communion.

Princeton Prof. Robert George applauded: "Abortion is the unjust taking of human life. It is not just something that is wrong like contraception, fornication or adultery. "It is a profound, deep injustice to deny to an entire class of people the protection of the law."

Sen. Kerry met privately with Washington Cardinal Theodore McCarrick. Last week McCarrick also saw Arinze in Rome, and later told the Catholic News Service, life issues such as abortion come first because "without life, you cannot have any other human values".

However, he added that the church is not a single-issue institution: "There are many issues that have to be considered."

He felt that bishops should not give "anybody direction on how they should vote." Nor would he deny Communion to anyone.

Prof. Michael Horan, a Catholic theologian at Loyola Marymount University, agrees with McCarrick: "Once you begin to deny any public figure Communion based on their public stance on one criteria, you open the door to chaos... Communion is not a right. It is a gift."

To date, most bishops agree.