COLUMBIA, S.C. — One day after Jon Huntsman formally suspended his campaign, Rep. Ron Paul said he has no plans to follow suit.

Mr. Paul, who has consistently trailed front-runner Mitt Romney in the polls, insisted that his campaign plays a valuable role keeping the spotlight trained on key issues, including slashing federal spending.

“To think that debating is not productive?” Mr. Paul scoffed at a press conference here. The Republican establishment might think “so-and-so’s going to win, so we better not discuss the issues anymore,” Mr. Paul said, but “I might just continue talking about cutting $1 trillion out of the budget. I think that’s legitimate.”

Mr. Paul spoke Tuesday at South Carolina’s statehouse, where he picked up the endorsement of three of the state’s conservative lawmakers days ahead of South Carolina’s GOP primary on Saturday. State Sens. Kevin Bryant, Lee Bright and Danny Verdin added their backing to that of state Sen. Tom Davis, who endorsed Mr. Paul on Sunday…