In a new television ad debuting Tuesday in Iowa, New Hampshire and South Carolina, GOP presidential candidate Mike Huckabee does the unthinkable - he wishes early voters "Merry Christmas."

Wearing a red sweater and standing before a glowing Christmas tree as "Silent Night" plays in the background, the former Arkansas governor asks viewers if they're "about worn out of all the television commercials you've been seeing, mostly about politics."

Behind Huckabee appears to be a white cross, which may be intersecting shelf lines or a window pane and slowly moves to the right on the screen until it's behind his head.

But the ordained Baptist minister, who has been riding a wave of evangelical support with his open religious appeals, said Tuesday that it's just a bookshelf and defended the ad.

"If we are so politically correct in this country that a person can't say 'enough of the nonsense with the political attack ads could we pause for a few days and say Merry Christmas to each other,' then we're really, really in trouble as a country," Huckabee said, speaking in Houston, Texas.

Click here to watch the ad titled, "What Really Matters"

In the ad, Huckabee says, "At this time of year, sometimes it's nice to pull aside from all of that and remember that what really matters is the celebration of the birth of Christ."

"I hope you and your family have a magnificent Christmas season. God bless you and Merry Christmas."[poll=11]

Catholic League president Bill Donahue said Huckabee went beyond wishing people a joyous holiday. Donahue said he was especially disturbed by the cross-like image created in the background of the ad, saying he believed it was a subliminal message.

"What he's trying to say to the evangelicals in western Iowa (is): I'm the real thing," Donahue said Tuesday on Fox News Channel's "Fox and Friends. "You know what, sell yourself on your issues, not on what your religion is."

Huckabee said the bookshelf is "nothing more than a bookshelf" and shrugged off the controversy: "I will confess this: If you play the spot backwards it says, 'Paul is dead. Paul is dead."'

He was joking about the Beatles' recording of "The White Album" and the urban legend that if a portion of the album is played backwards, the words "Paul is dead" is heard, a reference to the very much alive Paul McCartney.

Meanwhile, rival Mitt Romney launched a new TV ad yesterday slamming Huckabee, the ex-Arkansas governor, for commuting the sentences of 1,033 criminals - including 12 convicted murderers. "Huckabee granted more clemencies than the previous three governors combined," says the 30-second Romney attack ad.

"The difference between us is that I did something he never had to do. I carried out the death penalty 16 times, more than any other governor in my state's history," Huckabee told reporters in Los Angeles before attending a Beverly Hills fundraiser. "That's hardly soft on crime when you make that tough decision and actually carry it out."

Romney's state of Massachusetts does not have capital punishment.

The Romney-Huckabee spat continued throughout the day Tuesday.

"Interestingly, Mr. Romney has commended President Bush for the pardon of Scooter Libby, yet he brags that he never gave one as governor," Huckabee said in Houston.

Returning fire in Columbia, S.C., Romney reiterated that Huckabee is "liberal" on crime and immigration.

Asked about the Christmas ad, Romney said, "We recognize the diversity of faith and we unite over our commitment to religious liberty, and I hope Governor Huckabee, like all of us, is supportive to the diversity of faith and the liberty to worship God as they choose, and I trust that he and the other candidates will do just that."

Not surprisingly, Huckabee sounded Monday as if he wanted to declare a holiday truce among the Republican presidential contenders.

"I think the country could use a little good will and peace on earth a little more than they can some tit for tat in the political arena," Huckabee said.

FOX News' Carl Cameron, Serafin Gomez and Shushannah Walshe, and The New York Post and Associated Press contributed to this report.