House Majority Whip Jim Clyburn (D-S.C.) said on ABC's "This Week" Sunday that Sen. Bernie Sanders' identification as a democratic socialist may be an "extra burden" in down-ballot House races if he were to win the Democratic nomination.

Why it matters: Clyburn's comments echo fears from many establishment Democrats, who worry the House majority they won in 2018 by taking moderate seats carried by President Trump could be at risk with Sanders at the top of the ticket.

What he's saying:

"I think it would be a real burden for us in these states or congressional districts that we have to do well in. If you look at how well we did the last time, and look at the congressional districts, these were not liberal or what you might call progressive districts. These were basically moderate and conservative districts that we did well in. And in those districts, it's going to be tough to hold on to these jobs if you have to make the case for accepting a self-proclaimed democratic socialist."

— Jim Clyburn

What to watch: Clyburn, known as a Democratic kingmaker in South Carolina, said he will announce his endorsement for president on Wednesday, after the South Carolina debate.

The big picture: Sanders, the front-runner in the Democratic primary, has had to defend the label amid doubts about whether a democratic socialist can defeat President Trump.

Sanders defended his position at last week's Nevada debate: "We are living, in many ways, in a socialist society right now. Problem is, as Dr. Martin Luther King reminded us, we have socialism for the very rich, rugged individualism for the poor."

The other side: Mike Pence's chief of staff Marc Short said on "Fox News Sunday" that the Trump campaign is looking forward to a Trump-Sanders presidential race this fall.