Progressive leaders see Sen. Kamala Harris, if she's elected vice president, as their conduit to a post-Biden Democratic Party where the power will be in younger, more diverse and more liberal hands.

• Why it matters: The party's rising left sees Harris as the best hope for penetrating Joe Biden's older, largely white inner circle.

If Biden wins, Harris will become the first woman, first Black American and first Indian American to serve as a U.S. vice president — and would instantly be seen as the first in line for the presidency should Biden decide against seeking a second term.

• She'd face pressure to push Biden first on personnel matters.
• Progressives want Biden to look outside of his own network when filling administration positions, and prioritize inclusion across the Democratic caucus over working with moderate Republicans.

What they're saying: "If they are to be the transition and bridge to the New Democratic Party, that is the way in which they have to govern," Adrianne Shropshire, founder of BlackPAC, told Axios.

• "People believe Biden when he says 'Black Lives Matter' and 'We need to address racism in our nation,'" Shropshire added. "But they also believe he’s old school, and in order to solve these problems we actually need newer, progressive ideas — and voices that actually have some experience, direct or indirect, with the problems we’re talking about."
• "I hope she builds on being the only Black and Indian woman to ever serve in this role, but I’d love to see her also not treat that as symbolic," said Alicia Garza, co-creator of Black Lives Matter movement and founder of Black Futures Lab.
• "She’s going to put a racial and gender lens on everything that they talk about in their administration, and that’s been lacking," said Glynda Carr, founder of Higher Heights for America PAC, which focuses on electing progressive Black women to public office.

Be smart: This tees up potential points of tension between Harris and Biden right out of the gate.

The big picture: Harris wasn't a top choice for progressives during the Democratic presidential primary. But several who spoke with Axios for this story said there's a feeling that she's more accountable to their movement than Biden himself.

• The Senate in which she's served since 2017 views bipartisanship and what's possible between Democrats and the GOP differently than the Senate that Biden called home from the 1970s until he became Barack Obama's vice president. Progressives' standing inside the Democratic Party itself also has shifted.
• Just look at some of the task forces and commissions Biden has pledged so far, on topics ranging from immigration to police and court reforms, and think of how far apart Democratic and Republican politicians are.
• "Harris will be a voice pushing Biden not to negotiate with what the Republican Party wants to do," Waleed Shahid, spokesman for Justice Democrats, told Axios.

Between the lines: There are leftover strains of resentment toward the Obama-Biden White House, and a lessons-learned attitude, among progressives who felt Obama didn't prioritize them enough.

• "Progressives gave Obama a honeymoon in 2009 and then he appointed all these Wall Street people," Shahid said. "So we need to be vigilant" if Biden wins.
• "It should be a sigh of relief for Biden to have her ensuring that the troops are in line as they push for their agenda," Adam Green, co-founder of the Progressive Change Campaign Committee, said of Harris. "Because we know there will be underminers in his orbit."
• "There will definitely be corporate actors and establishment actors who urge them to trim their sails," Green said. "As the last person in the room, Senator Harris can play a key role in urging that they stay true to the bold ideas that they campaigned on and urging others not to get in the way of fostering party unity."

What we're hearing: Harris gained credibility among once dubious Democrats by grilling Republicans and Trump appointees in Senate confirmation hearings.

• On the campaign trail, her role includes outreach to increase turnout with Black and Latinx voters.
• She hits familiar themes about the public health and economic crises but also talks about "a long overdue reckoning on racial injustice in America," and calls President Trump a racist.

What's next: Policy areas activistshope would land in Harris' portfolio include criminal justice reform, systemic racism, voting rights and early-vote expansions, a COVID-19 relief package that addresses racial disparities, and accountability for tech companies.