This week, that border blew up into renewed conflict, in the bloodiest engagement in 40 years, which left more than 20 soldiers dead after a brutal fight with fists and clubs high in the mountains amid freezing temperatures and scant oxygen.
While both governments are now scrambling to deescalate, the conflict could provide the final push for a pivot already begun by New Delhi, away from Beijing and towards China's traditional rivals, the United States and Japan, as well as a growing regional one, Australia. As India seeks to push back against what many in the country view as Chinese aggression, it will rely on these allies more than ever.