It was a little different for me because I am a dual citizen
(Australia and the US). When I inquired they said I couldn't use my
Australian license in the US, even though I hadn't set foot in the US
in decades, because I maintained US citizenship, so I had to take US
tests and have a US callsign when visiting.

That's cos Australia and the US don't have a reciprocal agreement.

I'm dual citizen of Australia and the UK, and I can use my VK call in the UK
for up to 3 months if visiting. Not that I'd want to cos I still got my UK
license

I am surprised that the US don't issue temporary visitors licenses though.
Aus and UK do that.
--
Jack VK2CJC / MM0AXL
FISTS# 9666
Mid North Coast Amateur Radio Group
http://www.qsl.net/mm0axl/mncarg/index.html