The disappearing Muslim ban
Republican Presidential nominee Donald Trump participate in a town hall debate against Democratic nominee Hillary Clinton (L) at Washington University in St. Louis, Missouri, on October 9, 2016.
Another telling exchange during the debate was when Mr Trump was asked by an audience member to address the issue of Islamophobia.
The Republican candidate said it was "a shame", and then turned the answer into a discussion of the responsibility of American Muslims to report "when they see something going on".
He again repeated the unfounded allegation that neighours saw the San Bernardino attackers building bombs in their house but did not inform law enforcement.
When pressed by Raddatz on his proposed Muslim ban - which still is detailed on his campaign website - Mr Trump said it had "morphed into an extreme vetting".
He went on to detail a greatest hits rendition of his immigration policy. Syrian refugees could be a "Trojan horse". Illegal drugs are "pouring" over the US border with Mexico. Many undocumented migrants are criminals.
Mrs Clinton defended her call to increase the number of refugees admitted into the US and hit Mr Trump on his since-recanted Muslim ban.
"Donald has said, we're going to ban people based on a religion," she said. "How do you do that? We are a country founded on religious freedom and liberty."
Given that Mr Trump's proposal, while popular among Republican primary voters, is disfavoured by a majority of Americans, she wasn't going to let him off the hook easily.