Economist Thomas Piketty on Thursday urged former vice president and presumptive Democratic presidential nominee Joe Biden Joe BidenMomentum growing among Republicans for Supreme Court vote before Election Day Trump expects to nominate woman to replace Ginsburg next week Video of Lindsey Graham arguing against nominating a Supreme Court justice in an election year goes viral MORE to adopt economic proposals put forward by former presidential candidates Sens. Bernie Sanders Bernie SandersNYT editorial board remembers Ginsburg: She 'will forever have two legacies' Two GOP governors urge Republicans to hold off on Supreme Court nominee Sanders knocks McConnell: He's going against Ginsburg's 'dying wishes' MORE (I-Vt.) and Elizabeth Warren Elizabeth WarrenBiden's fiscal program: What is the likely market impact? Warren, Schumer introduce plan for next president to cancel ,000 in student debt The Hill's 12:30 Report - Presented by Facebook - Don't expect a government check anytime soon MORE (D-Mass.).

In a HillTV interview, host Krystal Ball asked the Paris School of Economics professor about what she described as a decreased focus by Democrats on “populist economic well-being” and an increased focus on issues important to wealthier white-collar professionals, and how the party could better appeal to a multi-racial working class coalition.

“I think you need to have a more ambitious policy platform of giving a better chance to more disadvantaged social and economic groups,” Piketty responded. “Let me remind you that the billionaire tax proposed by Bernie Sanders and Elizabeth Warren was actually pretty popular,” he added, noting widespread support for such proposals even among Republican voters.

“I think it would be a big mistake for the Democratic Party to abandon these kinds of ideas,” Piketty continued. “I think Joe Biden would be well-inspired to borrow some of the ideas put forward by Bernie Sanders and Elizabeth Warren, including the wealth tax.”

“I think it’s important to send a message to working America, to low-wage America, that you can have economic justice together with economic prosperity and in fact one of the big lessons from the history of American economic success is that you can have more economic prosperity with more economic justice,” he added.