The final question at the fourth Democratic presidential debate challenged candidates to share examples of surprising friendships they've had and how it's affected them.
The question on Tuesday was prompted by what many saw as an unlikely friendship between TV host Ellen DeGeneres and former GOP President George W. Bush, who sat next to each other at a football game together recently.
Two candidates named Republican Sen. John McCain: Sen. Amy Klobuchar and former Vice President Joe Biden, who delivered the eulogy at McCain's funeral.
In response, Meghan McCain tweeted a tribute to her father.
"I miss you so much Dad. You're absolutely everywhere and still so much alive in all our hearts. Inspiring everyone, everywhere," she tweeted.
Others also mentioned GOP colleagues. Sen. Bernie Sanders said Utah Sen. Mike Lee; Sen. Kamala Harris said Sen. Rand Paul; and Rep. Tulsi Gabbard said former Rep. Trey Gowdy.
Billionaire Tom Steyer said Deanna Berry, a black woman from South Carolina who serves as a community organizer for his campaign.
