If there are no clear rules, no, it's not legal (by definition, "law" is a set of clear rules).

If you decide that "no Chinese social network is allowed", you can create a law for that. But the TikTok ban is not like this.

If you care, you can find the clear rules here: https://en.m.wikipedia.org/wiki/RESTRICT_Act

Impact to the country's critical infrastructure and digital economy,

"Sabotage or subversion" of ICTS in the United States

Interference and manipulation of federal elections

Undermining the democratic process to "steer policy and regulatory decisions in favor of the strategic objectives of a foreign adversary to the detriment of the national security of the United States".

> Are national security arguments not legal?

Arguments aren't a source of law, and what's permissible in legislation is defined by the constitution.

> what's permissible in legislation is defined by the constitution.

Oh, sweet, summer child.

The constitution and the dozens of dozens of interpretations of the constitution by way of case law rendered by the supreme court.

Reading the full text of the constitution won't do much but put you a toe past the starting line in understanding what is and is not "constitutional" in the US.

If the data collected on TikTok is a national security issue, that would be a good admission since it would mean we'd have to pass some actual privacy laws in this country. Facebook/Google/Microsoft/etc collect the same kind of data, and their revenues are not as important to protect as our national security (I assume).

Same as in the US.

National security arguments can only go so far without falling afoul of Constitutional principles. Earlier versions of this bill failed because their breadth made it clear it could be used in situations not involving China or other 'bad' tech actors.

A blanket ban on "Chinese tech" is immeasurably broad, and would harm legitimate business interests. Should Microsoft, Cisco and Oracle stop doing business in the country if they're selling products and services to Chinese tech firms?

Correspondingly, Tencent has holdings in many American companies, Reddit and Twitter being two. Should Reddit be forced to buy out their holdings?

> Correspondingly, Tencent has holdings in many American companies, Reddit and Twitter being two. Should Reddit be forced to buy out their holdings?

I mean, yeah maybe. If there's a real national security risk it would make sense. Not that I think either of those companies are in any way trustworthy, but let's not compound the dangers to the public with CCP interference.

> If there's a real national security risk it would make sense.

Precisely. But as it stands, they even haven't made a case against Tiktok, let alone private investments by Chinese companies.

There's nothing stopping the DOJ from laying charges against Tiktok US (the corporation) if there's evidence of contravening US law. But there is plenty of political hay to be made by suspecting that there might be. What laws, you ask? That too hasn't been clear, which helps explain why these bills fail again and again.