let's change it to arizona and new mexico, since china doesn't border the us. if the us and mexico were one country a few decades ago, and the people in az and nm were ethnically mexican rather than american, and if the people in az and nm were bombed for saying they didn't like the us government, and if the people in az and nm voted to secede, and the if the us government bombed them harder until mexico supported them in their fight, and if that went on for over a decade until finally mexico just drove troops into az and nm... then yes i'd support giving those states up.
United States