If no nukes were used, US air force and Navy would immediately control the skies and seas. However, the world economy would die and Russia/North Korea and potentially Iran would join the Chinese. The Chinese are famous for sacrificing wave after wave of their seemingly endless population at opponents, so the bloodshed would be horrid. The EU would provide tactical support to US troops, but the war burden would basically be on the US and UK. EU and US would win, but they would want to haul *** out of their because you cannot occupy a nation of 1.3 billion. Everyone would be worse off in the long run. The invaders might try to free tibet and set up a democracy on the politically liberal, industrial east.