The US government can literally do this. They can print as much money as they feel like. It would be 'dumb' for sure, but the US treasury is indeed allowed to do this.
There was even talks of solving the national debt crisis by having Obama create a trillion dollar coin a couple years ago.
https://www.investopedia.com/ask/answers/082515/who-decides-...
The myth that the central bank prints money became prevalent following the Great Recession, when many were concerned about the unconventional policies of the central bank, which included intervention in the commercial paper market, mortgages and outright purchases of debt to keep the system from collapsing. By the end of the recession, the Federal Reserve had expanded its balance sheet by nearly $4 trillion.
The coin thing is a hack that would probably be challenged in court, because it's illegal for the Treasury to arbitrarily print money, except when it's silver.
So, you're not wrong in that the treasury can physically do those things, but it's in the same way that you wouldn't be wrong if you claim North Korea can do the same by illegally counterfeiting endless dollars.
Probably on some basis, but it would also probably survive the kind of challenge you describe.
> because it's illegal for the Treasury to arbitrarily print money, except when it's silver.
Platinum, actually, not silver. [31 USC § 5112(k)] Which is why minting the coin as a platinum coin was an essential component of the idea.
There is actually an interesting nugget in the Obama idea. The "trillion dollar coin" thing completely misunderstands market dynamics, but the idea of the Executive taking power back from The Federal Reserve is interesting.