For many months as Biden considered nearly a dozen women for the ticket, California Sen. Kamala Harris seemed like the most natural fit because of her resume, her visibility supporting the Black Lives Matter protests, and her championing of legislation to curb police brutality. But over the past week, long-held uneasiness among some close Biden allies about Harris' ambition and her attack on Biden during a June 2019 debate broke into the open.
Then this weekend, it was California Rep. Karen Bass' turn in the hot seat, as the Trump campaign highlighted her trips to Cuba as a young activist and questioned whether Biden would "put Castro-loving Communist Karen Bass a heartbeat away from the presidency" -- underscoring the potential risks for Biden in choosing a politician who is largely unknown as the other side races to define them.
Though vice presidential picks have rarely had a major effect on the outcome of an election, Biden's pick has taken on an outsized importance this year -- not only because of voters' concerns about his age, but also because in the midst of a pandemic and a painful recession, his team knows he must heed the first rule of vice presidential politics by picking a loyal partner who does no harm.
The spectacle of the vice presidential vetting process breaking into public view illustrated the difficulty of the decision facing Biden as he narrows his choice, as well as the behind-the-scenes maneuvering by the potential hopefuls and those who would vie to replace them in their current roles. (The current parlor game in California political circles, for example, is guessing who Democratic Gov. Gavin Newsom might appoint to an open US Senate seat if Harris vacates hers.)
Though Biden's team has kept the process secret, the former vice president made it clear from the beginning that he would pick a woman, and his team has vetted Bass, Harris and former Obama national security adviser Susan Rice -- who are widely viewed as top contenders -- as well as Massachusetts Sen. Elizabeth Warren, Illinois Sen. Tammy Duckworth and Florida Rep. Val Demings. Others under consideration include Atlanta Mayor Keisha Lance Bottoms and Michigan Gov. Gretchen Whitmer.
For many months, it was no secret that some of Biden's allies were still galled by Harris' attack on Biden during the 2019 debate in Miami, where she called out Biden's opposition to busing decades earlier as a young Delaware senator and his boasts that he had found a way to work with segregationist senators (comments she said she found hurtful).
The public airing of that grievance -- as well as widely circulated comments from some Biden backers that Harris is too ambitious and might be too focused on her own designs for the White House -- led to pushback from her allies this past week and from Harris herself on Friday.
Republicans have focused on Bass' description of Castro when he died in 2016. She expressed her condolences to the Cuban people and Castro's family: "The passing of the Comandante en Jefe is a great loss to the people of Cuba," Bass said in her statement, in what she has said was an attempt to translate "commander in chief." "I hope together, our two nations will continue on the new path of support and collaboration with one another, and continue in the new direction of diplomacy."
Bass has said she was not celebrating Castro's regime, and she told NBC's Chuck Todd on "Meet the Press" Sunday that she was "naive" in those years and emphasized that her more recent work in Cuba has focused on recruiting doctors to work in the inner cities of the US, because they come "tuition free."
"Now that doesn't excuse the fact that I know the Castro regime has been a brutal regime to its people," said Bass, who worked as a physician assistant before entering politics. "I know that there is not freedom of press, freedom of association."
When she used the term "comandante en jefe" in 2016, she said she did not see it as a phrase that was "endearing" to Castro, as many Floridians interpreted it to be. "Let me just say, Chuck, lesson learned. Wouldn't do that again. Talked immediately to my colleagues from Florida and realized that that was something that just shouldn't have been said."
Still, the Trump campaign is already using the Bass-Cuba connection to try to inflict damage on Biden in Florida, a crucial battleground state with a large and influential Cuban population.
On a Trump campaign press call Saturday, Florida Republican Sen. Marco Rubio said that if Bass became vice president, she would be "the highest-ranking Castro sympathizer in the history of the United States government. And it couldn't come at a worst time, when both regimes in Venezuela and in Havana are teetering on the brink of real collapse."
Bass, who is 66, was also forced to defend her faith Saturday on Twitter -- noting that she "proudly" worships at First New Christian Fellowship Baptist Church in South LA -- after the conservative outlet, the Daily Caller, resurfaced a video of her speaking at a 2010 opening of a Church of Scientology in Los Angeles.
She acknowledged that in the decade since that speech, "published first-hand accounts in books, interviews and documentaries have exposed this group" and that "everyone is now aware of the allegations against Scientology."
Duckworth, an Iraq veteran and Purple Heart recipient, could face pushback from the left-wing of the Democratic Party that she is too centrist at a time when Biden is trying to unite the party following his defeat of Vermont Sen. Bernie Sanders in the primary. Bottoms and Whitmer are both in key governing positions in states that have been ravaged by coronavirus, putting them in a tenuous and vulnerable position if they were to suddenly switch gears and focus on the presidential race.
Former Georgia state Rep. Stacey Abrams, who has actively campaigned for Biden's vice presidential slot, was asked about the potential disappointment that could ensue if Biden does not pick a woman of color for the post in the midst of a national reckoning on race relations.
"Joe Biden is going to pick the right partner for himself because he is the only person who has done this job," Abrams told CNN's Dana Bash on "State of the Union" Sunday. "While I believe that diversity is incredibly important and I think it is an absolute good to see a continued changing of the face of what leadership looks like in America, I look to Joe Biden to pick the right partner for himself in the moment that we have before us -- which is one of an economic crisis, a public health crisis, and a crisis of justice."
The Biden campaign is making history by vetting what is the largest and most diverse field of potential female vice presidential candidates ever. And in a deeply polarizing election cycle, as many Americans fight for their economic and physical survival, this group is likely to face more intense scrutiny than any group that has come before them in this final stretch.
This story has been updated with comments from Karen Bass and Stacey Abrams.