Former Vice President Joe Biden said he “expected” to be challenged by his rivals at the Democratic presidential debate but was “surprised” by the level of attacks against former President Barack Obama.

“I expected it,” Biden told reporters Thursday. “I was a little surprised at how much incoming was about Barack, about the president.”

Obama’s record on immigration was widely criticized by the candidates, and his signature legislative achievement, the Affordable Care Act, became a casualty of the discussion around “Medicare for All.”

Eric Holder, Obama’s attorney general, warned Democrats to tread lightly.

“To my fellow Democrats. Be wary of attacking the Obama record. Build on it. Expand it. But there is little to be gained — for you or the party — by attacking a very successful and still popular Democratic President,” he posted on Twitter.

But while the cannibalistic blitz gave Democrats pause, it gave Republicans reason to cheer.

“It was nice to see Democrats finally go after Obama’s failed policies very aggressively. Wish they would have done that years ago,” Donald Trump Jr. tweeted.

GOP strategist Rick Wilson chalked up the Democrats’ performance to their being inept at politics.

“I will always point to the fact that many of their leading candidates for 2020 spent last night taking a giant dump on Barack Obama,” Wilson tweeted. “It’s almost as if you’re trying to re-elect Trump, so go you.”

Sen. Kamala Harris, who sparred with Biden during the debate about their competing health care proposals, softened her stance Thursday.

“Many presidents before him tried to reform the American health care system. He actually got it done,” the California Democrat said.