German Cardinal Joseph Ratzinger, now Pope Benedict XVI, played an indirect role in the 2004 U.S. campaign when he directed Catholic bishops to deny Communion to abortion rights supporters such as Democratic presidential candidate John Kerry.

But Kerry, a lifelong Catholic and former altar boy, declined to criticize the new pontiff Wednesday.

"The election of a new pope is a great moment of hope, renewal and possibility for the Catholic Church," Kerry said in a statement.

Ratzinger, head of the Congregation for the Doctrine of the Faith, wrote a letter last June to U.S. bishops stating that Catholics who support abortion rights are guilty of a "grave sin" and are unworthy of Communion.

Although he did not mention Kerry or any other person by name, it was widely viewed that he was referring to Kerry when he said the sacrament should be denied in "the case of a Catholic politician consistently campaigning and voting for permissive abortion and euthanasia laws."

Further, his letter said any Catholic who votes for such a candidate is likewise "unworthy."

However, "Not all moral issues have the same moral weight as abortion and euthanasia," Ratzinger wrote. Disagreeing with the pope "on the application of capital punishment or on the decision to wage war" would not make someone unworthy to receive Communion.