President Donald Trump changed his anti-mask stance on Tuesday during a press conference, saying that masks "have an impact." Trump also wrote in a tweet on Monday that it is 'patriotic' to wear a mask and posted a photo of himself wearing one. This comes after months of the president refusing to wear a mask in public. Medical ethicist Art Caplan spoke with Boston Public Radio on Wednesday about Trump's revised stance on masks.

"[Trump's] anti-mask policy for the country was a failure, and I'm happy he's recognizing that," Caplan said. "[His change of opinion] comes too late, it probably cost tens of thousands of lives before he got around to admitting that his policy was wrong.

Trump has the power to influence his supporters' willingness to wear masks, Caplan noted.

"He has to role model for us," he said. "Many of the people who are in his camp will watch what he does."

Art Caplan is the Drs. William F. and Virginia Connolly Mitty chair and director of the division of medical ethics at the NYU Grossman School of Medicine.