> Legal tender has never been challenged in court to my knowledge

It was challenged and upheld, both as against debts before the the legal tender acts were passed and those after, by the Supreme Court in Knox v. Lee (1871).

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SJC_Hacker 6 days ago | parent [-]

Yet the US government can refuse payments in cash

https://www.federalregister.gov/documents/2017/10/03/2017-21...

	▲	ceejayoz 6 days ago \| parent [-]
		Yes. Because a patent filing fee is not a debt. (And because government can exempt itself from virtually anything not forbidden by the Constitution. This is why cops can break down your door, but I can't.)