WASHINGTON (MCT) — A Roman Catholic archbishop is threatening to deny Holy Communion to Rudy Giuliani over his support for abortion rights, spotlighting the ex-mayor's break from his church — and his political party — on an issue of critical importance to both.

St. Louis Archbishop Raymond Burke's comments threatened to reignite an issue that could prove troublesome for Giuliani among churchgoing Republicans — questions about how devoutly he practices his Catholic faith. Burke in 2004 also said he'd deny Communion to Democrat John Kerry.

In New Hampshire, Giuliani brushed off Burke's comments, saying, "Archbishops have a right to their opinion, you know. There's freedom of religion in this country."

Giuliani on Wednesday also stepped up his already fierce attacks on Democratic rival Hillary Rodham Clinton, comparing her to failed 1972 Democratic nominee George McGovern, who has become a symbol of the Democrats' liberal roots.

He said Clinton's comments about giving every U.S.-born baby a $5,000 savings bond are like "taking something from the George McGovern playbook" — namely, McGovern's idea to send every American $1,000. Giuliani, a former Democrat, didn't mention that he once supported McGovern.

Giuliani also jabbed Clinton for what sounded like an attempt to take on a Southern accent before a predominantly black audience in Alabama earlier this year.

Clinton spokesman Blake Zeff said, "It's unfortunate that the mayor's entire campaign is premised on attacking others instead of talking about what he would do if elected."

The archbishop's comments on abortion come as Giuliani already is trying to forestall a defection by religious conservative leaders to a possible third-party candidate.

Burke was asked recently whether he would deny Communion to Giuliani over the ex-mayor's personal support for abortion rights, despite the church's anti-abortion stance.

"If the question is about a Catholic who is publicly espousing positions contrary to the moral law and I know that person knows it, yes I would," he told the St. Louis Post-Dispatch.

Burke appeared to soften his comments slightly Wednesday, suggesting the politician in question would have to first be given a warning.

Giuliani, who once considered becoming a priest, has avoided describing how he practices his faith, saying that is a matter between him and his priest.