De-juro, US already uses metric - there's samples and document and stuff like that, just like in other countries. This makes it even more peculiar, because it's just the people that aren't willing to drop some old system that they brought from the colonial British Empire with them back in the day; you'd think it only makes sense, with all the freedom and independence tendencies, but somehow the archaic measuring system from the monarch is still vigorously beloved and defended by millions... even though they've declared independence from the monarch a couple of centuries ago.