By opting for a bold print and a mask matching her dress, Dr Biden knew her mask wouldn't be ignored - and she used that to make the strongest political point of the night. More than normalising mask wearing, she attempted to make it almost aspirational, sending a positive, uplifting message about masks.
Melania Trump, in her first appearance since contracting the virus, also donned a mask that matched her dress. However, hers was black - you know, the sort you'd wear to a funeral - and didn't generate quite as much dialogue online. But hey, credit where it's due, like Joe Biden's mask, Melania Trump's mask was dark and understated, but at least it was there. The same can't be said for her husband, who continues to walk into rooms full of people without covering his face, despite having had coronavirus.
While the men on stage argued over whether Covid-19 numbers were going up or down (they're going up) and whether or not more needs to be done (it does), Jill Biden made a statement that got through to people, judging by the reactions on social media and the headlines written about her mask after the debate.
She didn't argue against experts, she didn't try to make excuses - and with a bold pattern and bright colours, she also didn't play anything down.
Often seen as a frivolous topic, fashion is often used to get strong points across. Who doesn't remember the dozens of headlines written about Melania Trump's "I don't really care" jacket, on her trip to visit migrant children?
This is not the first time Jill Biden has used fashion to make a political statement in the pandemic. Over the past few weeks, she has been photographed multiple times wearing masks with the word "vote" on it.
Whether or not she intended her floral mask to ignite a conversation is not the point - the fact is that it did. And it sent the message that masks are something to embrace, not fear.
Women are often criticised for what they wear as society is desperate to place the focus on what a woman looks like rather than what she says. Jill Biden quietly managed to use one of society's most sexist traits to her advantage, making a point without saying a word.
And she said it with flowers.
