Tether is backed 1:1 with USD in traditional bank accounts. Some of it may still be seized and held by the US government, not sure if that's been resolved yet.
USDT also trades freely on open markets against USD. If USDT was being printed without USD backing then those markets would decouple.
USDT also trades freely on open markets against USD. If USDT was being printed without USD backing then those markets would decouple.