Former President Obama will tell Americans tonight that "democracy itself is on the line," setting the stage for a heavily personal and biographical appeal by Kamala Harris "for people to see themselves in her speech," advisers to both tell Axios.

Driving the news: Each is speaking on Day Three of the Democratic National Convention — with Harris capping the night when she formally accepts the vice presidential nomination on Joe Biden's ticket.

• Obama will frame the choice between Biden, who served as his VP for both terms, or a second term of President Trump, as a choice between hope and cynicism, an aide said.

Details: As the first Black woman and first Asian-American woman to be named to a major-party U.S. presidential ticket, Harris' speech is expected to draw on themes of diversity and inclusion.

• A Harris aide says she'll "tell her own story and highlight the examples and experiences of others."
• Obama will touch on Biden's experience steering the recovery after the 2008 financial crisis. He'll highlight what he sees as Trump's blunders on foreign policy, the economy and health care. He'll also critique moves by Trump to discourage or complicate voting — and urge Americans to vote early.

Between the lines: One veteran Democratic strategist outside the campaign says that while Harris' heritage speaks to themes of inclusion and representation, it isn't her defining characteristic — and that her work and political experience and skills as a communicator can appeal across wide swaths of the electorate.

• "Voters are looking for a team that can build us out of this mess and return us to competent government," the strategist said. "Kamala’s challenge tonight is to prove she’s that ticket."