In December, US President-elect Donald Trump urged the court to delay its decision until he returns to the White House to enable him to seek a “political solution” to resolve the issues at hand.
TikTok’s lawyer told the court on Friday that, as he saw it, the platform would “go dark” on 19 January without intervention.
Ms Prelogar, arguing for the US justice department, said “nothing permanent” had to happen on that day and there was still time for a sale.
Forcing the app to go dark could be just the “jolt” ByteDance needs to seriously consider a sale, she said.
“It will fundamentally change the landscape with respect to what ByteDance might consider,” she said, comparing the situation to “game of chicken” and one in which the US should not “blink first”.
The justices and will now consider their decision. A ruling is expected in the coming days.
More than a hundred people braved freezing conditions in Washington DC to attend the hearing in person.
Danielle Ballesteros, a student at UC San Diego, said had been waiting outside the court since 06:30 local time.
“I feel like TikTok doesn’t deserve to be banned,” she told BBC News.
While admitting to using it “probably too much”, she said she believes the app to be an important news source for her generation.
