The case concerns efforts by the Biden Administration to press sites such as Facebook, YouTube and Twitter to remove posts the White House deemed misinformation, primarily about COVID-19 vaccines and the 2020 election.

But Republican-led states Missouri and Louisiana, along with five individual social media users, sued, claiming this amounted to an infringement on freedom of speech.

Here's Louisiana Solicitor General Benjamin Aguinaga:

"But the government has no right to persuade platforms to violate Americans constitutional rights, and pressuring platforms in backrooms, shielded from public view is not using the bully pulpit at all. That's just being a bully."

The Biden administration countered that it was exercising its right to request the removal of what it believed to be content that harmed public health.

Here's Justice Department lawyer Brian Fletcher:

"I think it's really troubling the idea that those sorts of classic bully pulpit exhortations, public statements, urging actors to behave in different ways might be deemed to violate the First Amendment."

Questions posed by some of the justices focused on whether the plaintiffs had proper legal standing to sue, and how the government had caused harm.

Conservative Justice John Roberts said that the government is "not monolithic".

"I suspect when there's pressure put on one of the platforms or certainly one of the other media outlets, they have people they go to probably in the government to say, hey, they're trying to get me to do this. And that person may disagree with what the government's trying to do this. It's not monolithic. And that has to dilute the concept of coercion significantly, doesn't it?"

While liberal Justice Elena Kagan wondered whether the government was allowed to intercede in cases where content could cause harm:

"These platforms, they're compilers of speech and some part of the government, let's call it part of the law enforcement arm of the government says you might not realize it, but you are hosting a lot of terrorist speech, which is going to increase the chances that there's going to be some terrible harm that's going to take place. And we want to give you this information. We want to try to persuade you to take it down. The government can't do that?"

However, conservative Justice Samuel Alito expressed alarm at the pressure administration officials applied to social media platforms to target misinformation

"And so it's treating Facebook and these other platforms like their subordinates. Would you do that to the to The New York Times or The Wall Street Journal or the Associated Press or any other big newspaper or wire service?"

A lower court sided with the plaintiffs.

The Supreme Court's ruling is expected by the end of June.