JOE BIDEN isn’t the only 1970s-era pol whose views on school busing are coming in for fresh scrutiny.

A day after Biden was scorched for his views by Kamala Harris in the second round of Democratic presidential debates, Sen. Ed Markey’s Democratic primary opponent picked up on the issue and suggested the Massachusetts senator had also been on the wrong side of the busing debate.

Labor attorney Shannon Liss-Riordan tweeted, “Incredible job at the #DemDebate @KamalaHarris. Disappointed to learn that like @JoeBiden, @EdMarkey long opposed desegregation busing. Proud to be offering voters a choice here in Massachusetts in 2020 #mapoli.”

Harris, a first-term California senator, lit into Biden during Thursday’s debate over his past opposition to mandatory busing policies and his recent comments about working with segregationist Southern Democratic senators on issues of common concern.

Liss-Riordan, who announced last month that she would challenge Markey in next year’s Democratic primary, said on Friday that she watched the debate and was moved by Harris calling out Biden so passionately. She said she had not been aware of Markey’s past stance but “did some research” Thursday night.

“Even if it was many years ago, it makes a statement of a person’s values,” she said. “I am shocked that Ed Markey was a vocal opponent of busing to desegregate school for decades.”

Shortly after his election to the House of Representatives in 1976, Markey said he opposed busing to achieve racial integration in public schools, an issue that inflamed passions locally following the 1974 federal court order mandating that Boston begin busing students to desegregate its schools. Markey instead advocated for an increase of funding to schools and non-discriminatory hiring policies in local school committees, saying he did not believe busing would improve education quality. By 1984, he had dropped his opposition to court-ordered busing.

Markey’s office did not respond Friday to a request for comment on Liss-Riordan’s remarks.

A Brookline resident making her first run for public office, Liss-Riordan has made her name by winning major concessions on behalf of workers from corporations like Uber, Lyft, Starbucks, and American Airlines.

Biden, who served more than three decades in the Senate from Delaware before being tapped as Barack Obama’s running mate and then serving eight years as his vice president, was a major player in a group of Republican and Democratic senators who sought to block the use of federal funds to enforce desegregation of schools through busing. He went as far as to back the idea of a constitutional amendment that would have prohibited court-ordered busing.

“It was hurtful,” Harris said in Thursday’s debate to hear Biden speak of his bonds with Southern senators known for their racist views.

She also told the story of a little girl who was in an early wave of children to integrate schools in California, ending the anecdote by saying: “That little girl was me.”