Former Mississippi governor Haley Barbour speaks during the 2014 Republican Leadership Conference on May 3 in New Orleans, La. (Justin Sullivan/Getty Images)

NEW ORLEANS -- Former Mississippi governor and national GOP chairman Haley Barbour on Friday delivered an impassioned defense of Republican pragmatism -- even as the tea party attempts to take out his longtime home-state ally, Sen. Thad Cochran (R-Miss.).

Barbour didn't mention Cochran or his opponent, state Sen. Chris McDaniel, in his speech at the Republican Leadership Conference, but the primary this coming Tuesday was clearly on his mind.

“In a two-party system, purity is the enemy of victory," Barbour said, repeating a construct he has used before.

Barbour mentioned previous examples of the tea party nominating a candidate who later went on to lose in a winnable race, focusing in particular on Christine O'Donnell's primary win over then-Rep. Mike Castle in the 2010 Delaware Senate race.

He noted that outside groups spent heavily for O'Donnell in the primary.

(Correction: Barbour mentioned the Club for Growth, but the Club never backed O'Donnell. This post has been updated to reflect this.)

“People got a right to nominate whoever they want to nominate," Barbour said. "But that’s not the point. The point is, in the name of purity, we defeated a guy who was going to get 70 percent of the vote. And we elected a guy who votes with us 5 percent of the time.”

Barbour also noted that, when faced with a split Congress, Ronald Reagan worked with Democrats.

“Reagan compromised on everything," Barbour said, adding: "It’s idiocy to think 60 million (Republican voters) can agree on everything."

“We have to learn to be for what you’re for, absolutely, but to tolerate people who don’t agree with you on everything," he said.