Former President Barack Obama says that the United States is at “an inflection point” following the assassination of conservative activist Charlie Kirk and that President Donald Trump has further divided the country rather than work to bring people together.

“There are no ifs, ands or buts about it: The central premise of our democratic system is that we have to be able to disagree and have sometimes really contentious debates without resorting to violence,” Obama said Tuesday night during an event in Erie, Pennsylvania, hosted by the Jefferson Education Society, according to a transcript obtained by The Associated Press.

“And when it happens to some, but even if you think they’re, quote, unquote, on the other side of the argument, that’s a threat to all of us,” he said. “And we have to be clear and forthright in condemning them.”

Obama has kept somewhat of a low profile in his post-presidency. Responding to a moderator’s questions Tuesday, he addressed Trump’s rhetoric after Kirk’s assassination, as well as other administrative actions.

The Democrat spoke about his own leadership following the 2015 slaying of nine Black parishioners at a Charleston, South Carolina, church, as well as Republican then-President George W. Bush’s actions following the Sept. 11 terrorist attacks. He said he sees the role of a president in a crisis “to constantly remind us of the ties that bind us together.”

The sentiment among Trump and his aides following Kirk’s killing of calling political opponents “vermin, enemies … speaks to a broader problem,” Obama said.