That's not the way it works. Bipartisan votes in Congress don't alter the constitution, or expand Congress's own power under the constitution, unless the vote is for a constitutional amendment, which must subsequently be ratified by the states to become effective.

Yeah, I didn't say that.

Firstly, they didn't expand or alter the Constitution.

I'm not sure where you got that from. Reading back and I don't see it anywhere.

Stated again, hopefully more clearly; by exercising restrictions on China they've reestablished that China is not "the people" described in the Constitution. So, it's not protected from congressional acts.

And second, they didn't need to do that anyway. Foreign policy is a power reserved for Congress and the President. No amendment ever restricted that power.

See Article 1.

Amendment I takes precedence over Article I. Congress does not itself get to decide what "the people" refers to in the Constitution, and acts of Congress do not alter or establish any meaning of any terminology in the Constitution. Where there is ambiguity, the courts resolve it -- Congress does not have the final say in interpreting the rules that define and limit its own power.

Further, the protection of free speech in the first amendment does not even refer to "the people", but simply prohibits Congress from abridging the freedom of speech per se, without qualification or any exception for who is doing the speaking. Congress cannot pass laws that abridge the freedom of speech as a matter of actual effect, regardless of whether they are doing so under the auspices of exercising other powers.

Foreign policy powers don't come into it -- if the act restricts free speech, it is unconstitutional, regardless of what end Congress was attempting to pursue.