Former White House press secretary Sarah Huckabee Sanders apologized Thursday after viciously mocking Joe Biden s stuttering in Thursdays Democratic debate in a post that stunned the former vice president and other critics.

Biden snapped back: Its called empathy. Look it up.

After Sanders first message was flooded with furious responses, she insisted in a follow-up tweet that she was not trying to make fun of anyone with a speech impediment. Then she deleted the tweet. Then she apologized.

Biden, who has himself battled to overcome stuttering, was actually demonstrating a stutter during the debate. He said he keeps in touch with people who have reached out to him for help. The little kid who said, I-I-I cant talk. Wh-wh-what do I do? I have scores of these young women and men who I keep in contact with, he said.

Sanders initially reacted with a tweet reading: I I I I I I I I I I I I I I I hhhave absolutely no idea what Biden is talking about.