NEW ORLEANS (CNA) — While Gov. Haley Barbour has told the Southern Republican Leadership Conference that primary voters should not expect a “perfect candidate” or demand “purity,” commentator Deal Hudson says Republicans must have a “pro-life and pro-marriage” nominee to attract Catholic voters.

“It’s not a matter of demanding ‘purity’ from a candidate, but, rather, a matter of expecting principle and prudence. It’s a matter of principle because the Catholic Church teaches, and most Americans agree, that unborn life should be protected and that marriage is between a man and a woman,” Hudson said.

Selecting such a nominee is also a matter of “political prudence” because a nominee who is not pro-life and pro-marriage will not be able to “ignite the Catholics, evangelicals and other social conservatives at the grassroots whose commitment and passion will determine the outcome of the 2012 election,” he said.

Hudson’s comments came June 18 at a social-issues panel held at the conference under the sponsorship of the Susan B. Anthony List. At a prior conference event,

Barbour spoke to attendees about the need to rally around a Republican nominee.

“In politics, purity is a loser,” while party unity “wins elections,” said Barbour, a Mississippi Republican.

“You are going to disagree with something about the candidate,” he added.

Barbour discussed his vision for a campaign that was focused on the economy and light on social issues.

He argued that the Tea Party movement cannot effectively serve as a third party, which would split the conservative vote.

Hudson, who led Catholic outreach for George W. Bush’s candidacy in 2000 and 2004, said the campaigns’ focus on reaching Mass-attending Catholics resulted in a swing of 15% more Catholics voting for the GOP nominee between 1996 and 2004.

“That’s the kind of swing that changes the outcome of an election,” Hudson said.

Barbour also said that prospective candidate and former Utah governor Jon Huntsman’s support for civil unions for homosexual couples was troubling and could be an “obstacle” for his candidacy.

“Any time you don’t have the platform position, you have to explain why not,” he said, according to The New York Times.

The Southern Republican Leadership Conference had more than 2,000 attendees. Speakers included presidential hopefuls former Pennsylvania Sen. Rick Santorum, former House Speaker Newt Gingrich and Reps. Michelle Bachmann, R-Minn., Ron Paul, R-Texas, and Herman Cain, R-Georgia.

Both Catholic candidates, Santorum and Gingrich, were received “warmly and enthusiastically,” Hudson reported.

Louisiana Gov. Bobby Jindal, a Catholic, also spoke at the conference.