Democratic White House hopefuls questioned Obama's policies, particularly on immigration, health care and trade, during Wednesday night's debate, largely as a way to try to target former Vice President, who is an early front-runner for the party's 2020 nomination.

But Senate Democrats, as well as high-profile officials within the party, rallied to Obama's defense on Thursday, questioning the wisdom of criticizing a former president who remains popular in the party.

"I mean, you can disagree with him, and I have, but the bottom line is he was our party standard-bearer, he was the leader of our nation. He did an extraordinary job and I think he should be given that recognition by those who are running for president," Durbin said.

"I think President Obama is a very, very popular figure in America to this day because he did a very good job. Did he accomplish everything? No. You compare the Obama administration to this administration, it's night and day and Americans are realizing that," Schumer said.

Progressive candidates have embraced "Medicare for All" and similar proposals, viewing the Affordable Care Act, the signature health care law of the Obama administration, as inadequate. It's a shift from the 2018 elections when warning that Republicans were trying to nix the health care law and its benefits was central to the Democratic strategy to win back the House.

During Wednesday night's debate, New York City Mayortook aim at Obama's record on deporting immigrants, while Julián Castro, Obama's Housing and Urban Development secretary, said Biden hadn't "learned the lessons of the past," referring to the Obama administration.