Joe Biden has vowed to choose a woman as his running mate if he's the Democratic presidential nominee. Here's a look at a shortlist of frequently mentioned potential candidates — each of whom would bring something different to the ticket.
It just depends on what the former vice president is looking for — age, ideology, race, experience and geography could all matter.
1. Kamala Harris
Biden became the 2020 Democratic front-runner in the first place largely because of the overwhelming support he's received from African American voters.
Key Democratic groups, as well as the powerful Rep. Jim Clyburn, D-S.C., have not been reluctant to suggest that Biden would be wise to choose a woman of color as his running mate — and one of the top names mentioned has been Harris, including by Clyburn himself.
Harris, 55, a senator from California, would help balance a ticket led by a 77-year-old white man and could help further cement the party's relationship with the most loyal Democratic voters in the country (94 percent of black women voted for Hillary Clinton over Donald Trump in 2016, according to exit polls).
She may, however, face continued questions over her record as a prosecutor and attorney general in California, including a controversial decision to prosecute parents of truant children and an appeal of a California court ruling that had declared the death penalty unconstitutional.
A recent internal poll of members conducted by She the People, a group of women of color, found Harris to be one of two top contenders.
2. Stacey Abrams
Abrams is regarded as a rising star in the party, and her presence on the ticket, political strategists told NBC News, could electrify voter turnout in Georgia, which could help put either of the state's Senate seats in play (there are elections for both this fall).
And at 46, she would create important generational balance on the ticket and might even help Biden draw in younger Democratic voters — many of whom have opted for Bernie Sanders during the primaries.
But Abrams is also likely to face concerns over not being qualified to step in if Biden became unable to carry out his duties as commander in chief.
Abrams, the former minority leader of the Georgia state House, who narrowly lost her bid for governor in 2018 amid widespread claims of voter suppression, was the other top contender in the She the People internal poll — and the personal preference of the group's leader.
"On a personal note, I believe the most qualified candidate for VP is the country is a progressive woman of color: Stacey Abrams," said Aimee Allison, the founder and president of She the People.
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3. Amy Klobuchar
The senator from Minnesota, who as a presidential candidate frequently pitched her crossover appeal with GOP voters, could help Biden build his own electability message with disaffected Republicans unhappy with Trump.
She also might boost Biden's prospects in Michigan, Wisconsin and Pennsylvania, which, like Klobuchar's home state, are upper Midwest battlegrounds crucial for a path to victory.
Klobuchar's decision to drop out and endorse Biden ahead of Super Tuesday was credited with helping him quickly consolidate the moderate faction of the Democratic Party and cruise to a series of critical victories.
Klobuchar, however, wouldn't bring a lot of balance to the ticket, Democratic political strategist Joel Payne said.
"Philosophically, she is maybe too much of the same thing as Joe Biden," Payne said.
Payne also suggested that passing over African American women like Harris and Abrams risks "reinforcing some of the negative thinking about how African American voters are treated as part of the Democratic coalition — that they are leveraged for turnout but not prioritized."
4. Elizabeth Warren
The senator from Massachusetts has the clear progressive bona fides needed to bring in voters from that wing of the party.
And Biden, in recent days, has begun actively courting them, having endorsed Warren's proposal to bolster bankruptcy protections for people struggling financially.
Warren wouldn't face any questions about her readiness to take over for Biden.
But Biden has explicitly pitched himself as "a bridge" to a new generation of Democratic candidates. And while Warren proved to have mass appeal among younger progressive voters, at 70, she might not be in the best position to be the future face of a post-Biden party.
5. Gretchen Whitmer
The Michigan governor turned heads after delivering the Democratic Party response to Trump's State of the Union address last month.
Her age — 48 — gives her the ability to be the future of the party, while her standing as a governor dispels any notion that she wouldn't be able to step in for Biden. And her being from an upper Midwest swing state bodes well for the geographic mix of the ticket.
One possible issue? She said Monday she didn't think she'd be the one.
"It's not going to be me," Whitmer said during an interview on MSNBC.
Other women who have been frequently mentioned by politicians, strategists and voters include Rep. Val Demings, D-Fla., who commanded attention as a House manager during Trump's impeachment trial; Sen. Catherine Cortez Masto, D-Nev., the preference of former Senate Democratic leader Harry Reid; New Mexico Gov. Michelle Lujan Grisham; and New Hampshire's pair of senators, Jeanne Shaheen and Maggie Hassan.
Adam Edelman reported from New York and Alex Seitz-Wald from Washington, D.C.
CORRECTION (March 16, 2020, 8:50 p.m. ET): An earlier version of this article misstated the party to which Rep. Val Demings of Florida belongs. She is a Democrat, not a Republican.