At no point did the US have enough silver or gold to cover their obligations for all currency in circulation.

That’s my point.

You can make it worth whatever you want but if you’re not guaranteed to be able to redeem it, you’re calling that currency on something else.

That something else is the US military, ultimately.

My comment was directed at your statement "that at no point in history was the US dollar 100% backed by gold (or silver, originally). Never." which is entirely false. The US dollar (the currency unit), was at one point quite literally an exact weight of silver. This is no longer the case, but it was true in the past. This has nothing to do with the nation debt, or what is backing it. Obviously, the national debt isn't collateralized by precious metals or anything else except the military and power to raise taxes.