It takes a lot for C-Span to get mad.
But an unusual move by the South Carolina Democratic Party to bar the network from putting on a live broadcast of its annual convention — which is doubling as a major showcase for 21 presidential candidates — has left executives at the strait-laced public affairs network fuming. CNN and Fox News aren’t thrilled about it, either.
The source of the friction is a deal struck between the state party and MSNBC, the liberal-leaning cable network, granting the channel exclusive rights to show the candidates’ speeches live on Saturday.
Under the party’s rules, which were abruptly announced this week, rival television networks will have to wait three hours after the event concludes before broadcasting their footage.
News organizations always scrap for exclusive interviews with prominent politicians. But the South Carolina convention, virtually a required stop for presidential hopefuls, is typically open to all journalistic comers. The decision to restrict coverage set off broader concerns that the state party was picking and choosing the news organization allowed to cover what is a crucial event in an early-voting state.
“This has never happened before, ever,” said Steve Scully, the C-Span political editor, who has overseen the channel’s campaign coverage since the early 1990s.
Mr. Scully, who also hosts C-Span’s popular call-in show, is perhaps best known for a stoic onscreen demeanor that remains in place even when callers rant and complain. On Wednesday, Mr. Scully sounded more animated.
“You have what is an open event, and a political party dictating who can and cannot carry it live,” he said in an interview. “It really is a very undemocratic move. If they’re trying to get access to the widest audience possible, why not let everyone in?”
C-Span lodged a formal complaint on Wednesday with the convention’s organizers, calling their move “the antithesis of openness” that “could set a precedent that would end up seriously limiting citizen access to key presidential electoral events.”
Fox News, which was also barred from broadcasting the event live, said it planned to sign the C-Span letter and had lodged its own complaint.
In an interview, a spokesman for the South Carolina Democratic Party, Tim Sullivan, disputed the notion that networks had been “barred” from covering the convention, though he conceded that MSNBC had indeed been granted the exclusive live rights.
Mr. Sullivan said the decision was part of a broader agreement with MSNBC that, he argued, would enhance the proceedings. Two MSNBC hosts, Joy-Ann Reid and the Rev. Al Sharpton, are set to interview each of the Democratic presidential candidates from a set constructed inside the convention hall.
“This is probably one of the first times that a major state convention is going to have a show broadcasting from inside of it,” Mr. Sullivan said, adding: “We wanted to put on this big show for our convention-goers and for our viewers.”
MSNBC declined to comment.
Mr. Scully, of C-Span, said he went public with his objections in an effort to prevent a troubling precedent. C-Span, he noted, has generated a library of decades’ worth of unfiltered appearances by presidential candidates, useful for historians and citizens alike.
“I worry it could be the start of a slippery slope,” he said.