COLUMBIA, S.C. — Less than a year ago, South Carolina’s top Democrat was predicting that Joe Biden could win the state’s critical early primary “going away” if he were a candidate. As the Democratic field has expanded — and with Biden possibly just days away from entering himself — House Majority Whip Jim Clyburn is being more cautious.

“Well, not going away maybe,” Clyburn told NBC News during an interview on the steps of the South Carolina capitol Tuesday. “When you get this many people into a race you have no idea how the spread will occur. What I do know is, according to all the polls I’ve seen in South Carolina and around the country, he is the leading contender among Democratic voters. Now, how big that lead is I think depends upon whether or not any of the other people catch fire. And some of them may.”

The two men have been friends for decades, and Clyburn said the two spoke as recently as three weeks ago. Even though he said he has not been told about Biden’s final decision, he offered some advice, suggesting that Biden's focus should be about the country’s future.

He also advised Biden against something the former vice president's team has considered: naming a vice presidential running mate at the same time he announces his candidacy.

“I think that we have to be careful about doing cute things in campaigns,” he said. “I think it would be a mistake for Joe Biden to come out – or any other candidate – and announce a running mate right out of the gate.”

Clyburn, who said he does not plan to endorse in the race, expects about half of the Democratic contenders to attend his annual fish fry fundraiser, scheduled for June 21.

Asked about former Rep. Beto O’Rourke’s candidacy ahead of his first trip to South Carolina, Clyburn questioned whether the enthusiasm that brought him to nearly upset Texas Sen. Ted Cruz last November would carry over into 2020.

“His [challenge] is whether he’s able to show that same kind of energy, intensity, and fundraising capacity that he did against Cruz. I’m not too sure that that can happen in the presidential race. But if he can, he’s going to be very formidable,” he said.