Yes, they can just buy from existing miners, with a bit of a premium if they want the equipment fast. Also any first world government can easily mass produce ASIC equipment if they wanted to do it, there's no technical hurdles.
Hmm... then why are the vast majority of ASIC manufactured in China?
(the hurdles are perhaps more economic as well as social)
I am pretty sure Australia (the first world country that I come from) could *not* do this as they don't manufacture nearly *any electronics* nowadays.