Recalling the assassinations of Robert F. Kennedy and Martin Luther King Jr. in 1968, former Vice President Joe Biden on Friday asked a rally audience to contemplate what would have happened if former President Barack Obama was killed before the 2008 election.

Speaking passionately about his last year of law school in 1968, Biden remembered how Kennedy and King, his two political heroes, were assassinated within weeks of each other. Kennedy was killed as he was running for president and was the presumptive nominee for that year's election.

"My senior semester they were both shot and killed," Biden said to the crowd in Hanover, New Hampshire. "Imagine what would have happened if, God forbid, Barack Obama had been assassinated after becoming the de facto nominee. What would have happened in America?"

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Biden was talking about how the upheaval of his youth propelled him into a political career. He was successfully elected to the Senate at age 29 in 1972.

Biden's words were considered controversial as Obama was the first black president of the U.S., and chose Biden as his own running mate.

Former Vice President Joe Biden speaks during a campaign event at Dartmouth College, Friday, August 23, 2019, in Hanover, New Hampshire. Elise Amendola / AP

Biden also revealed that many people believed he was gay due to his support for the Equal Rights Amendment in the 1970s.

"I remember because I was such a big supporter of the E.R.A in 1972, quote — to show you how things have changed, thank God — "Well, you know why Biden is for the E.R.A., he's probably gay." Not a joke," Biden said.

Although Biden is considered the frontrunner in the race and a leader in the polls, he has been criticized for his age and his tendency to make controversial comments.