WASHINGTON — Bernie Sanders claimed that “racist efforts” are behind the moves to undermine President Obama.

“What you are seeing today in this Supreme Court situation is nothing more than the continuous and unprecedented obstructionism that President Obama has gone through,” Sanders said at a town hall in Columbia, South Carolina, Tuesday night.

Republican Senate leaders announced Tuesday they would ignore any nominee Obama puts forward to succeed Justice Antonin Scalia, arguing that the next president should make the decision.

“And this is on top of this birther issue, which we heard from Donald Trump and others — a racist effort to try to de-legitimatize the president of the United States. Can you imagine that?

“To say, well, he’s not really the president. He wasn’t born in the United States, which is nonsense,” Sanders continued.

“My dad … came from Poland. I’m running for president. Guess what? Nobody has asked for my birth certificate. Maybe it’s the color of my skin, I don’t know.”

The forum came just days before Democratic voters — including a large number of African-Americans — head to the polls Saturday in South Carolina.

Sanders and Hillary Clinton both spoke directly to the issue of combating racism at the town hall.

An African-American student told Clinton she’s been treated differently since wearing her hair natural and asked how the former secretary of state could improve race relations.

White people must be “honest” that their life experiences may make them unable to understand the “systemic racism” African-Americans face daily, Clinton responded.

“You have a right to wear your hair any way you want to,” Clinton told the young woman. “As somebody who has had, you know, a lot of different hairstyles. I say that from some personal experience.”