Biden thinks that's a good thing, but questioned Warren's standing as a frontrunner in comments to reporters in Ohio on Wednesday.
"Well, it's kind of about time other people get questioned," he said. "You know, I haven't seen any polling showing that nationally, on average, that anybody else is a frontrunner. You guys keep talking about that."
"I think Elizabeth Warren's done very well," Biden added. "She's moved, but now that she has moved and is taken more seriously, people are going to ask her about a little candor here. Tell us how you're going to do what you say you're going to do"
The Massachusetts senator has led Biden by a slim margin in several national polls and in some early voting states like Iowa. While Biden had a significant lead on both Warren and Vermont Sen. Bernie Sanders earlier this year, data shows Warren steadily closing that gap.
Warren faced attacks at the debate from South Bend, Indiana, Mayor Pete Buttigieg and Minnesota Sen. Amy Klobuchar, who both pressed her on issues such as her Medicare for All plan.
Warren has repeatedly skirted a direct answer when asked if her plan will require tax increases on the middle class, something Biden has criticized her for heavily. But she maintains that overall costs will go down.
“It’s fascinating that the person who has a plan for everything has no plan for the single most consequential thing in this election in the minds of the American people, across the board," Biden said Wednesday.
Medicare for All will cost at least $30 trillion over 10 years — and it will be paid for in part by raising taxes on middle class families.— Joe Biden (@JoeBiden) October 16, 2019
Joe Biden has a better plan — he will protect and build on Obamacare to ensure everyone has access to quality, affordable health care. pic.twitter.com/Yg5auxKojQ
At the debate, tensions flared between Biden, whose vision for the Democratic Party includes an approach akin to the Obama-Biden administration, and Warren, who is an icon for some in the more progressive wing in the party.
When Warren discussed her work on the Consumer Financial Protection Bureau during the Obama era, Biden jumped in, saying he had rounded up votes in the Senate for it. "Let's get that straight," he said.
Warren responded after a pause, "I am deeply grateful to President Obama, who fought so hard to make sure that agency was passed into law."
Biden later cut her off, "You did a hell of a job in your job."
“Thank you,” Warren deadpanned.
Biden on CFPB, which Warren helped create: "I went on the floor and got you votes. I got votes for that bill. I convinced people to vote for it"— Axios (@axios) October 16, 2019
Warren: "I am deeply grateful to President Obama."
Biden: "You did a hell of a job in your job."
Warren: "Thank you." pic.twitter.com/TQJzMGWfQF
This article originally appeared on USA TODAY: Joe Biden digs at Elizabeth Warren on Medicare for All, polling numbers