While former Vice President Joe Biden currently leads amid a growing group of 2020 Democratic hopefuls, Sen. Kamala Harris of California says Biden would be a great running mate – as her vice president.

Harris, one of the leading Democratic candidates, has repeatedly dismissed concerns that a woman is not electable after Hillary Clinton's unsuccessful 2016 White House bid.

While stumping Wednesday in Nashua, New Hampshire, Harris said she believed Biden would be a great running mate since he already has the credentials and has “proven that he knows how to do the job.”

After serving 36 years in the Senate, Biden was vice-president from 2009 to 2017 under Barack Obama. Biden unsuccessfully ran for president in 1988.

Both Harris and Massachusetts Sen. Elizabeth Warren have been routinely dismissed as capable of taking on President Trump in 2020, not because of their programs or policies, but their gender.

Harris also challenged Biden’s claim that the 1994 crime bill he voted for did not lead to mass incarceration.

"I have a great deal of respect for Vice President Joe Biden, but I disagree. That crime bill ... did contribute to mass incarceration in this country," Harris told reporters.

In addition to Harris and Warren, there are three other notable women vying for the Democratic nomination: Rep. Tulsi Gabbard of Hawaii, Sen. Kristen Gillibrand of New York and Sen. Amy Klobuchar of Minnesota.