(CNN) -- Sen. Hillary Clinton's aides blasted Sen. Barack Obama's campaign Monday after a major Obama supporter referenced the blue dress at the heart of former President Bill Clinton's impeachment scandal.

Obama defended his church in a radio interview on the "Michael Smerconish Show" that aired Monday.

Gordon Fischer, a former chair of the Iowa Democratic Party and part of Obama's Iowa support team, also compared Bill Clinton unfavorably to Joe McCarthy.

McCarthy was a senator who was known for leveling accusations that people were Communists or spying for the Russians in the 1950s.

"When Joe McCarthy questioned others' patriotism, McCarthy (1) actually believed, at least aparently (sic), the questions were genuine, and (2) he did so in order to build up, not tear down, his own party, the GOP," Fischer, wrote on his blog.

"Bill Clinton cannot possibly seriously believe Obama is not a patriot, and cannot possibly be said to be helping -- instead he is hurting -- his own party. B. [Bill] Clinton should never be forgiven. Period. This is a stain on his legacy, much worse, much deeper, than the one on Monica's blue dress."

Fischer was referring to Bill Clinton's comments over the weekend that a race between Sen. John McCain and Hillary Clinton would be a contest between two people who love their country. Some Obama supporters -- including former Air Force Gen. Tony McPeak -- have interpreted that statement as an attack on Obama's patriotism.

Fischer, who endorsed Obama last fall, later removed the post from his blog and replaced it with an apology.

"I sincerely apologize for a tasteless and gratituous [sic] comment I made here about President Clinton. It was unnecessary and wrong," he wrote.

In a conference call with reporters Monday, Clinton aides said Fischer's decision to attack the New York senator reflected "gutter tactics that [the Obama] campaign is now deploying."

"This is now the Obama campaign's primary message to the American people," said spokesman Howard Wolfson. "Not to build him up, but to tear Sen. Clinton down."

He also dismissed Fischer's apology. "In my opinion the remarks of Gordon Fischer are very much in keeping with the campaign Sen. Obama is running. So I don't know why he would apologize."

Clinton aides also distanced themselves from remarks made this weekend by Clinton supporter and CNN analyst James Carville.

Carville told the New York Times Saturday that New Mexico Gov. Bill Richardson's endorsement of Obama "came right around the anniversary of the day when Judas sold out [Jesus] for 30 pieces of silver."

On Monday, Carville defended his comments. Watch more of Carville's interview »

"That's exactly what I said and ... I think the quote had the desired intent ... that people saw Richardson and saw somebody who is disloyal," Carville told Wolf Blitzer. "I'm very satisfied with the response I gave."

Carville also said he hadn't spoken with Hillary Clinton about Richardson's endorsement, but that he was outraged.

"I doubt if Gov. Richardson and I will be terribly close in the future," he said, but "I've had my say ... I got one in the wheelhouse and I tagged him."

On Monday, Richardson said Democrats need to "stop the bloodletting" so the party can unify before the convention.

"We're fighting each other, so we've got to end this," Richardson said on CNN's "American Morning."

Richardson, a former member of the Clinton administration, said he almost endorsed Clinton right after her husband visited him to watch the Super Bowl. Watch Richardson explain why he picked Obama »

Meanwhile, Clinton returned to the campaign trail Monday to take on the economy in a policy address in Philadelphia, Pennsylvania.

She said the country's economic crisis "is, at its core, a housing crisis," and called on President Bush to appoint an "emergency working group on foreclosures." Watch Clinton talk about a "crisis of confidence" »

Obama is in the middle of a three-day vacation in the U.S. Virgin Islands, following the hit he took following the flap over his former minister, the Rev. Jeremiah Wright.

Some of Wright's old sermons came under fire after a news report this month turned some of his most controversial comments into a YouTube phenomenon. In one, the minister said America had brought the September 11 attacks upon itself. In another, he said Clinton had an advantage over Obama because she is white. Watch a report on the role of politics in the pulpit »

In a radio interview on the "Michael Smerconish Show" that aired Monday in Philadelphia, Obama defended the church, saying it is "not some crackpot church," and pointing out that Bill Clinton also had ties to Wright.

Clinton invited Wright to the White House when he was going through his impeachment crisis.

McCain, the presumptive GOP presidential nominee, is in California Monday, where he's holding two fundraisers.

The Arizona senator raised $11 million in February, compared with $55 million for Obama and $34.5 million for Clinton. E-mail to a friend

CNN's Rebecca Sinderbrand contributed to this report.

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