The Atlantic staff writer Anne Applebaum introduced the Ukrainian leader.
The respondents cited the 89-year-old senator's latest illness as the reason she should resign.
Police arrested the Missouri man on multiple charges, including attempting to kidnap or kill the president, vice president or family member.
Videos include stock imagery from Russia, Ukraine, Italy and Estonia.
Some graduates plan to turn their backs to stage as the daughter of the Russian opposition leader gives her speech.
“It was eerie, even creepy," the Connecticut senator said.
“I have been in those rooms with him when he met with those leaders, I believe they think he's a laughing fool," he said.
“He's got no personality. And I don't think he's got a lot of political skill,” the former president said of the Florida governor.
The Justice Department is “considering its options,” he added.