COLUMBIA, South Carolina — Two Republican presidential candidates would do away with the National Labor Relations Board if elected, they said Tuesday at a forum sponsored by the South Carolina Chamber of Commerce. The NLRB has come under fire from the GOP since it blocked Boeing from moving a plant to South Carolina to punish striking workers in Washington state. When asked what the NLRB would look like in his administration, Texas Gov. Rick Perry replied succinctly, “There wouldn’t be one.” Former House Speaker Newt Gingrich, asked the same question, offered a similar response. “If I were Speaker of the House right now, I would have defunded the NLRB,” Gingrich said, before adding that he was exploring whether he’d have the authority to sign an executive order ending the agency.