"The original sin of slavery" Biden on race

Former Vice President Joe Biden while on the campaign trail attended service on Sunday (September 15) at the Birmingham, Alabama church where an infamous 1963 bombing killed four young black girls.

Biden, who served under the first black U.S. president and enjoys strong support from likely black primary voters, has also drawn criticism for his response to whether Americans had a duty to repair slavery's legacy.

"Lynch mobs, arsonists, bomb makers, lone gunman... We all now realize, this violence does not live in the past. The same poisonous ideology that lit the fuse on 16th Street pulled trigger at Mother Emanuel," Biden told the gathering at 16th Street Baptist Church in reference to a deadly 2015 mass shooting by a white supremacist at a mainly black church in Charleston, South Carolina.

The 1963 bombing was seen as a tipping point in the fight for racial equality in the United States and eventually led to the passage of the 1964 Civil Rights Act that outlawed racial segregation.

Biden has made several verbal slips up around the black experience in the U.S. including suggesting bringing social workers into black families' homes to "help them deal with how to raise their children" and having a "record player on at night" to help with language acquisition.