"What he's done is elevate the conversation to talk about a real issue and a real threat," she said.
Trump had sparked criticism from Britain's highest officials
Wednesday when he retweeted three anti-Muslim messages from Jayda Fransen, the deputy leader of the group, Britain First. Trump's support for the messages, which contained videos depicting purported Muslims assaulting people and smashing a statue of the Virgin Mary, drew condemnation from England, including from Prime Minister Theresa May.
"I don't believe so," Sanders said when asked if Trump knew who Fransen was.
But, as she had done on Wednesday, Sanders then defended the retweets, saying they were an attempt by Trump to get a conversation started on security and immigration.
"I believe he knew what the issues are," she said. "And that is that we have a real threat of extreme violence and terrorism, not just in this country but across the globe, particularly in Europe, and that was the point he was making."
Sanders had made a similar case on Wednesday, downplaying questions about whether the videos were authentic because "the threat is real."
"That is what the President is talking about, that is what the President is focused on, is dealing with those real threats, and those are real no matter how you look at it," she had said.
Fransen heralded Trump's backing.
"GOD BLESS YOU TRUMP!" she wrote in all caps on Wednesday after the President's retweets.