Twitter users were quick to point out her error and thousands of users tagged their posts with #KatrinaPiersonHistory to sarcastically blame any and everything on Obama:
In an appearance on CNN on Wednesday, Pierson stood by her comments, saying that her point was that "Donald Trump wasn't there," and added that Khan's father, Khizr Khan, is a "strong supporter of Sharia law."
However, Khizr Khan has previously disavowed the religious law.
Sharia law includes a "tremendous discrimination of genders," he told CNN, "which disqualifies them under the Constitution of the United States."
He emphasized his position by reminding viewers that he preaches reading and abiding by the Constitution.
"I do not stand for Sharia law because there is no such thing (under the Constitution)," he said.
Trump has attacked the Khan family numerous times since Khizr Khan and his wife, Ghazala, appeared at the Democratic National Convention last week and condemned the GOP nominee as failing to adhere to the Constitution, pointing to his proposal to ban Muslim immigrants.