The Pledge of Allegiance is an oral statement in which US citizens vow to be loyal to their country. It was first penned in 1892 by socialist minister Francis Bellamy, but is still recited schools across the US every day.
Often, people stand to recite the pledge and place their hands over their hearts.
However, footage emerged last week of the First Lady remaining silent while it was read out on the anniversary of the 9/11 terrorist attack.
Husband Donald Trump could be seen mouthing the words whilst standing beside her.
Twitter users clashed over the footage. One called Mrs Trump’s decision not to recite the pledge as “disgraceful to watch.”
Another user wrote: “Trump and Melania should be asked spontaneously to recite the Pledge of Allegiance with no teleprompter to help them. My guess is neither know it.”
And another said: “She doesn’t know the words, guys. She doesn’t care about the US. She’s only ever cared about her prospects for wealth.”
Other users argued the First Lady’s silence during the pledge was within her rights.
One said: “There are many people in this country that do not recite the Pledge of Alligence.
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“I remember his hands behind his back with his head down and eyes closed. And what’s wrong with that? Not a damn thing!”
It is not a legal requirement to recite the patriotic oath because US citizens are allowed to exercise free speech under the First Amendment in the nation’s constitution.
The pledge reads: “I pledge allegiance to the flag of the United States of America, and to the republic for which it stands, one nation under God, indivisible, with liberty and justice for all.”
Last year, the pledge made international headlines after an 11-year-old boy from Flordia was arrested following his refusal to recite it.
The student of Lawton Chiles Middle Academy in Lakeland declined to stand up for the pledge, resulting in a row with a substitute teacher.
The teacher, Ana Alvarez, reportedly insisted the student take part despite pupils being within their rights to refuse to do so.
The student then left the classroom and “created another disturbance” which led to his arrest, according to the Lakeland Police Department.
They continued: “To be clear, the student was not arrested for refusing to participate in the pledge; students are not required to participate in the pledge of allegiance.”
School officials said the teacher, who was later banned from working in schools run by Polk County Public Schools, was “not aware” students could refuse to take part in the pledge.