WASHINGTON, March 18 (Reuters) -

U.S. Supreme Court justices on Monday appeared skeptical of

a challenge on free speech grounds to how President Joe Biden's

administration encouraged social media platforms to remove posts

that federal officials deemed misinformation, including about

elections and COVID-19.

The justices heard oral arguments in the administration's

appeal of a lower court's preliminary injunction constraining

how White House and certain other federal officials communicate

with social media platforms.

The Republican-led states of Missouri and Louisiana, along

with five individual social media users, sued the

administration. They argued that the government's actions

violated the U.S. Constitution's First Amendment free speech

rights of users whose posts were removed from platforms such as

Facebook, YouTube, and Twitter, now called X.

The case tests whether the administration crossed the line

from mere communication and persuasion to strong arming or

coercing platforms - sometimes called "jawboning" - to

unlawfully censor disfavored speech, as lower courts found.

Biden's administration has argued that officials sought to

mitigate the hazards of online misinformation, including false

information about vaccines during the pandemic that they said

was causing preventable deaths, by alerting social media

companies to content that violated the platforms' own policies.

Justice Department lawyer Brian Fletcher told the justices

that the government may not use coercive threats to suppress

speech, but it is "entitled to speak for itself" by informing,

persuading or criticizing private speakers.

The plaintiffs have argued that platforms suppressed

conservative-leaning speech, which they attribute to government

coercion, a form of state action barred by 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 told Benjamin Aguinaga,

Louisiana's solicitor general, that the government is "not

monolithic" and when the government applies pressure, a platform

or media outlet "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."

Roberts added: "That has to dilute the concept of coercion

significantly, doesn't it?"

Conservative Justice Samuel Alito expressed alarm at the

pressure administration officials applied to social media

platforms to target misinformation, treating them as

"subordinates," demanding answers, exhorting them to be

"partners," and "cursing them out" when dissatisfied.

"I cannot imagine federal officials taking that approach to

the print media," Alito said.

Fletcher noted that the context was "a time when thousands

of Americans were still dying every week, and there was a hope

that getting everyone vaccinated could stop the pandemic. And

there was a concern that Americans were getting their news about

the vaccine from these platforms, and the platforms were

promoting - not just posting, but promoting - bad information."

"I know the objectives were good," Alito responded, but said

he doubted the federal government treated print media the same

way.

Conservative Justice Brett Kavanaugh suggested such

interactions might not be unusual. There are "press people

throughout the federal government who regularly call up the

media and berate them," Kavanaugh said.

Fletcher said the challengers in the case lacked the proper

legal standing to bring the lawsuit in the first place "because

they have not shown an imminent threat that the government will

cause a platform to moderate their posts in particular."

Aguinaga said the administration's actions were "not using

the bully pulpit at all. That's just being a bully."

Liberal Justice Ketanji Brown Jackson described a

hypothetical scenario in which social media platforms allowed

posts challenging children to jump out of windows at

increasingly heights, with serious injuries and deaths

resulting.

"Is it your view that the government authorities could not

declare those circumstances a public emergency and encourage

social media platforms to take down the information that is

instigating this problem?" Jackson asked Aguinaga.

Government officials could call the platforms to say it is a

problem, Aguinaga responded. But the moment that the government

presses them to take down the posts, "that is when you are

interfering with third-party speech rights," Aguinaga added.

The justices in February heard arguments in another social

media case over whether to uphold laws passed in Texas and

Florida that would restrict the content moderation practices of

platforms.

In the case argued on Monday, the plaintiffs sued officials

and agencies across the federal government, including in the

White House, FBI, surgeon general's office, Centers for Disease

Control and Prevention and the Cybersecurity and Infrastructure

Security Agency.

Louisiana-based U.S. District Judge Terry Doughty issued a

preliminary injunction in July 2023 that barred an array of

government officials from communicating with platforms regarding

content moderation, such as urging the deletion of certain

posts.

The New Orleans-based 5th U.S. Circuit Court of Appeals

subsequently narrowed that order. The Supreme Court put the

injunction on hold pending the review of the case by the

justices.

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