Usually, the special guests whom presidential nominees invite to their debates are meant to underscore some central theme of the candidate's agenda or uplifting moment in their biography.
This year, the guests in the spotlight underscore how much the candidates dislike one another. Both Hillary Clinton and Donald Trump will be bringing people whose purpose for coming appears to be antagonizing their opponent.
Here's who will be in the guest seats in Las Vegas on Wednesday night:
Donald Trump’s guests
Malik Obama. President Obama's estranged half-brother opposes gay marriage, is angry about the overthrow of Libya's former dictator and likes Trump's campaign slogan.
Kenyan-born Malik Obama, who has homes in Africa and Washington, voiced his grudges with the president in a July interview with the New York Post. He said Libyan dictator Moammar Kadafi was a friend.
The president's half-brother, a polygamist with multiple wives, also begrudges Barack Obama and Clinton for supporting same-sex marriage, though Trump also calls himself a champion of gay rights. And Trump's vow to protect Israel also appears to put him at odds with Malik Obama, who has aligned himself with the Palestinian terrorist group Hamas.
"I like Donald Trump because he speaks from the heart," Malik Obama told the Post. "'Make America Great Again' is a great slogan. I would like to meet him."
On Wednesday, he will likely get his chance.
Patricia Smith. Patricia Smith's son, Sean, was killed in the 2012 terrorist attacks in Benghazi, Libya. She lays blame for his death on Clinton, and she accuses the former secretary of State of lying to her about what happened in the Libyan city in the aftermath of the attacks.
Clinton has vehemently denied ever giving Smith false information, and her campaign notes that the accusations Smith makes about Clinton's handling of Benghazi conflict with the findings of several government investigations.
Sarah Palin. Palin, the former Alaska governor and the 2008 Republican vice presidential nominee, endorsed Trump during the GOP primaries.
James O'Keefe. Conservative activist James O'Keefe will attend, according to Bloomberg News. O'Keefe makes undercover videos in which he seeks to entrap government officials, advocacy organizations and others into making compromising comments that reveal what he alleges is corruption and abuse.
The productions of his group, Project Veritas, are often selectively edited. But they have attracted considerable media attention, particularly on Fox News. O'Keefe's highest-impact video involved staff at the advocacy organization ACORN appearing to offer actors posing as a prostitute and her boyfriend advice on how to avoid getting caught engaging in such illegal activity as human trafficking and child prostitution. But investigators at the California attorney general's office ultimately found O'Keefe's work to have been "severely edited" and misleading. A probe by the U.S. Government Accountability Office found ACORN had not misused any federal funds.
Trump campaign CEO Steve Bannon also said to CNN on Wednesday that the campaign had invited other guests who will "expose Bill and Hillary's sordid past."
Hillary Clinton’s guests
Meg Whitman. Hewlett-Packard CEO Whitman is a former GOP gubernatorial nominee in California and one of the most prominent defectors from the Republican side of the presidential race this year. Her presence campaigning and raising money for Clinton reflects the deep uneasiness so many moderate and Republican women have about Trump.
In a private meeting with some of the biggest donors in the GOP, Whitman compared Trump to Hitler and Mussolini as she asked House Speaker Paul Ryan how he could in good conscience support such a nominee, according to the Washington Post.
Mark Cuban. The presence of billionaire Mark Cuban at the first presidential debate touched off the war of the guests this year. Trump threatened that if Cuban came to the event as Clinton's guest, he would bring the women who accused Bill Clinton of unwanted sexual advances.
By the second debate, Trump made good on his promise, though his campaign's plan to have the women confront Bill Clinton just before the event started was thwarted by the debate commission. Now, Cuban is back. After the first debate, Clinton had taunted Trump by mentioning Cuban was her guest and that he "is a real billionaire, by the way" – a reference to reports that Trump has inflated his wealth.
Kareem Abdul-Jabbar. The basketball great has excoriated Trump in several columns published in the Washington Post, warning readers that the GOP nominee is xenophobic and paranoid.
Clinton also invited several other guests. They include:
Leon Panetta. Former U.S. Defense secretary and White House chief of staff under former President Bill Clinton.
Karla Ortiz. A Nevada resident whose parents are undocumented and at risk of deportation.
Astrid Silva. A "Dreamer" and activist from Nevada.
Ryan Moore. A man with spondyloepiphyseal Dysplasia dwarfism who has known Hillary Clinton since 1994 and is featured by the campaign often praising her compassion.
Ofelia Diaz Cardenas. A Mexican immigrant who was fired from her housekeeping job with Trump International after wearing pro-union buttons, but was later reinstated after federal labor officials intervened.
Family and friends of Pvt. Damian Lopez-Rodriguez. Lopez-Rodriguez was an undocumented immigrant when he was killed serving the U.S. Army in Iraq.
Pastor Robert E. Fowler Sr. Senior pastor, Victory Missionary Baptist Church in Las Vegas.
Kevin Hooks. President, Las Vegas Urban League.
Dolores Huerta. Labor leader and civil rights activist; co-founder of the National Farmworkers Assn.
Gene Karpinski. President, League of Conservation Voters.
Jonathan Nez. Vice president, Navajo Nation.
Arturo Rodriguez. President, United Farm Workers.
Stephanie Schriock. President, Emily's List.
D. Taylor. President, UNITE HERE.
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6:30 p.m.: This story was updated with additional guests.
5:15 p.m.: This story was updated with additional guests.