In short, the anniversary of 9/11 is a complicated occasion in a maelstrom of a year, as the US grapples with a health crisis, searches its soul over racial injustice, and prepares to choose a leader to chart a path forward.
Still, 9/11 families say it's important for the nation to pause and remember the hijacked-plane attacks that killed nearly 3,000 people at the trade center, at the Pentagon, and near Shanksville on September 11, 2001, shaping American policy, perceptions of safety, and daily life in places from airports to office buildings.
“I know that the heart of America beats on 9/11 and, of course, thinks about that tragic day. I don’t think that people forget,” says Anthoula Katsimatides, who lost her brother John and is now on the board of the National September 11 Memorial & Museum.
Friday will mark Trump's second time observing the 9/11 anniversary at the Flight 93 memorial, where he made remarks in 2018.
Biden spoke at the memorial’s dedication in 2011 when he was vice president.
The ground zero ceremony in New York has a longstanding custom of not allowing politicians to speak, though they can attend.
Biden did so as Vice President in 2010, and Trump as a candidate in 2016.
Though the candidates will be focused on the commemorations, the political significance of their focus on Shanksville is hard to ignore: Pennsylvania is a must-win state for both.
Trump won it by less than a percentage point in 2016.