It's hardly unusual to see former primary rivals come together once the presumptive nominee is chosen, but their past clashes are striking in light of this week's running mate announcement.
Let's roll the tape:
1. HARRIS CRITICIZES BIDEN'S STANCE ON BUSING AT FIRST DEMOCRATIC PRIMARY DEBATE
In what became her most memorable debate moment, Harris challenged Biden's opposition to federally mandated busing when he was in the Senate, telling him she benefited from the program to integrate schools. The face-off produced Harris' "That little girl was me" remark that drew widespread media attention.
2. HARRIS BLASTS BIDEN FOR HYDE AMENDMENT FLIP-FLOP
Harris called Biden's past support for the Hyde Amendment "unacceptable" at a Democratic primary debate, citing her role as a former prosecutor who tried rape and child molestation cases. Biden defended his record, saying he supports a women's right to choose. Harris pressed him, asking why it took him so long to change his position on the Hyde Amendment.
During Biden's tenure in the Senate, he had expressed support for the amendment, which prohibits the use of federal funds to subsidize abortions except for cases of rape and incest or when a woman's life is endangered.
3. HARRIS AND BIDEN CLASH OVER HEALTH CARE PLANS ON DEBATE STAGE
Before Harris backed off a full-scale "Medicare-for-all," she was vehemently arguing for it in the early primary debates, pressing Biden who has always said that single-payer health care would cost too much. The two went at it over this issue.
"The plan, no matter how you cut it, costs $3 trillion when it is, in fact, employed, number one. Ten years from now, after two terms of the senator being president, after her time. Secondly, it will require middle-class taxes to go up, not down. Thirdly, it will eliminate employer-based insurance. And fourthly, what happens in the meantime?" Biden said. Harris responded that the cost of doing nothing was too high.
4. HARRIS SAYS SHE BELIEVES BIDEN'S ACCUSERS OVER SEXUAL HARASSMENT CLAIMS
“I believe them, and I respect them being able to tell their story and having the courage to do it,” the California senator told reporters in April 2019. Biden at the time had been accused by a number of women of inappropriate touching and kissing, including by a Nevada politician who said he came up behind her at a 2014 campaign stop and kissed her on the back of her head.
5. HARRIS SAYS BIDEN SHOULDN'T HAVE USED 'LYNCHING' WHEN REFERRING TO CLINTON IMPEACHMENT
After President Trump referred to his impeachment process as a "lynching," video emerged of Joe Biden using the same language to refer to then-President Bill Clinton's impeachment in 1998. Harris was pressed on this and said it was right for Biden to apologize