With their microphones muted unless it was their turn to speak, according to the debate rules, body language took on outsized importance for Harris and Trump.

Harris in particular leaned into the nonverbal communication, keenly aware that her every reaction was being broadcast to the world, “speaking” to the audience even while Trump ostensibly had the floor. Networks showed a split screen with both candidates for most of the debate.

The topic took over social media well into Wednesday.

This was Trump's face at the exact moment Kamala Harris said people were leaving his rallies out of boredom pic.twitter.com/4P3hdpxATY

— Conspiratorial Templates (@mynamehear) September 11, 2024

The debate can be summarized in facial expressions. pic.twitter.com/omati470Ck

— Maggie Hennefeld (@magshenny) September 11, 2024

Kamala just blinked the 10 loudest blinks in American history pic.twitter.com/HKUu0ejQW5

— Joey Nolfi (@joeynolfi) September 11, 2024

Kamala is serving FACE Harris Trump debate #Debate2024 pic.twitter.com/3nXwYgYC21

— Stuart Brazell (@stuartbrazell) September 11, 2024

Trump looks like it's his first night ever having a human face and he's testing out what it can do every time Harris is talking pic.twitter.com/y1t39NwANz

— Janel Comeau (@VeryBadLlama) September 11, 2024

At various points she looked amused or befuddled by whatever Trump was saying, as if w ordlessly saying he was lying. A few times she dramatically put her fingers under her chin, eyes wide, head tilted. Other times she laughed.

Trump sometimes scowled, sometimes smiled curtly. His eyes flashed anger or annoyance, perhaps even boredom at times. He rarely looked at Harris while she spoke, instead pointing his face forward toward the cameras or ABC News moderators.

When the candidates did have the floor, Trump and Harris both gesticulated with their hands, mannerisms that are by now familiar to Americans who’ve spent a lot of time watching them.