ABC

Texas governor and Republican presidential candidate Rick Perry calls his rival Mitt Romney's work at Bain Capital a potentially "fatal flaw" which could imperil Republican chances to win back the White House in November.

Perry, who is trailing badly in the polls, spent the week attacking Romney as a "vulture capitalist," whose work at Bain allowed him to reap huge profits by dismantling companies and laying off workers.

Perry's criticism has sparked a backlash by some prominent Republicans.  Former New York Mayor Rudy Giuliani denounced the attacks as "ignorant and dumb."  Fox News host Sean Hannity compared them to the rhetoric of Occupy Wall Street.  And influential Sen. Jim DeMint, R-S.C., warned that Perry's charge "really gives the Democrats a lot of fodder."

This morning, Perry told me he has no regrets. 

"This is not something that we knew wasn't coming up," Perry said on "This Week."  "It's better to be talking about it here in January in South Carolina than it is in September and October with a nominee.  So if it's a fatal flaw, then we need to talk about it now."

Perry said he's not ready to buy into Romney's claim that he created more than 100,000 jobs while at Bain, telling me, "I think the question is out there and it's a good conversation to have.  We're going to get tested by Obama and his group, so you better have all of these answers done early.  No surprises in September and October."

Perry, once considered a strong contender for the Republican nomination, placed a disappointing fifth in the Jan 3 Iowa caucuses.  That night, he told supporters he was heading home to Texas to "reassess" his campaign.  Many thought he would give up the fight, but Perry quickly returned to the trail.  He has invested heavily in South Carolina, the first primary in the South, which takes place on Saturday.

When I asked him if he'd drop out if he fails to finish first or second in the Palmetto State, Perry told me: "We'll make that decision on Saturday.  Our intention is to win South Carolina and go forward from there.  But to try to plan your campaign months in advance, I think is a little bit of a stretch."

Watch my full interview here.