Republican presidential front-runner Mitt Romney appeared Thursday to have successfully blunted attacks on his work at Bain Capital, with still more conservatives coming to his defense, his rivals backing down and voters at campaign stops in South Carolina saying they disapproved of the critique.

But several Republicans said Romney still faces the challenge of persuading blue-collar voters in this recession-hit state that his stewardship of Bain — and the casualties in jobs and factories sometimes left in its wake — was ultimately good for the economy.

The debate over Romney’s business record may be an early test of what is all but certain to become a general-election debate if the former Massachusetts governor wins the GOP nomination.