(CNN) Joe Biden is partially embracing progressives' call for free public college tuition, backing a plan to make universities tuition-free for those whose families make less than $125,000 per year.

The former vice president's move, announced by senior aides on a call with reporters hours before his Sunday night debate with Vermont Sen. Bernie Sanders, is Biden's latest olive branch to the left as he attempts to consolidate the party behind him and pivot to a general election against President Donald Trump.

It comes the same weekend Biden adopted Massachusetts Sen. Elizabeth Warren's proposed bankruptcy reforms, which would undo major parts of a law the two had fought over 15 years ago, when Biden was a Delaware senator and Warren was a professor.

Biden, who has amassed a delegate lead on Sanders and is looking to all but clinch the Democratic nomination in Tuesday's primaries in Arizona, Florida, Illinois and Ohio, is increasingly seeking to embrace popular proposals from his current and former opponents. He had previously called for community college to be tuition-free.

"This continues the tone you have heard from Vice President Biden over the last couple of weeks that as Democrats we are united and we are looking forward to truly pulling this party together," a senior Biden campaign aide said on the Sunday conference call.

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