In particular, I see no reason to highlight the US Debt vs. that of
other countries or regions other than as a political statement.
The US debt has many digits, and is published regularly by an agency
with a tradition of not fudging the data. It's a perfectly reasonable
source of randomness. It's a large number because the US is a large
rich country.
I suppose the Japanese debt might be a usable substitute for next
time, since it's also a large rich country with a large debt.
R's,
John