Hillary Clinton to speak at DNC as Harris looks to make history as 1st female president

Former Secretary of State Hillary Clinton will speak Monday on the first night of the Democratic National Convention in Chicago, where later this week Vice President Kamala Harris will formally accept the party's nomination for president.

Harris will be the second woman in history to do so following Clinton, whose monumental 2016 run made her the first woman to clinch a major party's nomination, though she went on to lose the general election to Donald Trump -- Clinton famously conceding she had failed to shatter the "hardest glass ceiling."

Clinton endorsed Harris the same day President Joe Biden announced he was leaving the 2024 race and backing his vice president to take his place atop the ticket. In a joint statement with her husband, former President Bill Clinton, Clinton said she was "honored" to endorse Harris and would "do whatever we can to support her."

"We've lived through many ups and downs, but nothing has made us more worried for our country than the threat posed by a second Trump term … Now is the time to support Kamala Harris and fight with everything we've got to elect her. America's future depends on it," their statement read.

Comparisons of Clinton and Harris' campaigns have begun to emerge as Harris ramped up her operation in the weeks after Biden's decision to step aside.

Several Democrats told ABC News they are feeling buoyed by Harris' candidacy and how she's reenergized the party, but are worried about being overconfident against Trump after what transpired with Clinton eight years ago.

Clinton, who first ran for president in 2008 but lost in the primary race to Barack Obama, was successful in 2016 in clinching the nomination after defeating independent Sen. Bernie Sanders.

A bitter, ugly general election contest ensued between Trump and Clinton. Trump took to calling Clinton "Crooked Hillary" and the "devil." Clinton called half of Trump's supporters a "basket of deplorables," which critics called a mistake that alienated some voters.

A Trump fundraising email sent out Monday hours ahead of Clinton's DNC remarks highlighted her past "deplorables" comment and claimed she was "about to unleash hell on MAGA."

Polls in 2016 had shown Clinton ahead leading up to Election Day, but when results came in they showed Trump leading a stunning upset by grabbing several key battleground states. Clinton conceded the next morning.

"I know we have still not shattered that highest and hardest glass ceiling, but some day someone will and hopefully sooner than we might think right now," Clinton said in her concession speech.

Clinton later recounted her experiences in greater detail and what went wrong with her campaign in her 2017 memoir "What Happened." She wrote that she bore responsibility ultimately for the loss to Trump but described it being difficult to overcome stereotypes.

"A lot of people said they just didn't like me. I write that matter-of-factly, but believe me, it's devastating," Clinton wrote. "But I think there's another explanation for the skepticism I've faced in public life. I think it's partly because I'm a woman."

She also directed some blame at former FBI director James Comey for reopening the investigation into her private email server 11 days before the election.

After the 2016 election, Clinton maintained a relatively low profile until 2020 when she campaigned for Biden after his success in the Democratic primaries.

Clinton spoke at the 2020 Democratic National Convention, saying she wish Trump had been a "better president" and praised Biden's character and his choice of Harris to be his running mate. She said they were a team who could "pull our nation back from the brink and build back better."

More recently, she penned a New York Times op-ed offering Biden advice on how to debate Trump before the June CNN showdown. Clinton called Trump a bully who "stalked" her on the debate stage in 2016 and urged Biden to be "direct and forceful."

After Biden dropped out of the race, in large part because his poor debate performance ignited Democratic fears about his age, Clinton wrote another Times op-ed offering a full-throated endorsement of Harris.

Clinton said that Harris can defeat Trump but warned she will face similar prejudices.

"I know a thing or two about how hard it can be for strong women candidates to fight through the sexism and double standards of American politics. I've been called a witch, a 'nasty woman' and much worse. I was even burned in effigy," Clinton wrote.

Clinton added, "Ms. Harris will face unique additional challenges as the first Black and South Asian woman to be at the top of a major party's ticket. That's real, but we shouldn't be afraid. It is a trap to believe that progress is impossible."