“China’s military could take the territory by force, but maintaining the gains in the long term would be exceptionally difficult,” Hu said, noting the tough terrain.

Yet with both nations undertaking massive naval modernizations and brushing up against each other’s interests across South Asia and in the South China Sea, the festering dispute risks being the catalyst for a violent flare-up, some security analysts say.

STRING OF PEARLS

For thousands of years, Chinese and Indian empires were kept apart by the Himalayas. After years of fast economic growth, the rivals now have the resources to consolidate and patrol their most distant regions.

India is starting to feel fenced in by Chinese agreements with its neighbors that are not strictly military but could be leveraged in a conflict.

Indians sometimes refer to these as a “string of pearls,” which includes China’s force deployments in Tibet, access to a Myanmar naval base, and Chinese construction of a deepwater port in Hambantota, Sri Lanka, and another in Gwadar, Pakistan.

Some in the Chinese government worry that India is becoming part of a U.S. strategy to contain China. The United States has sold $8 billion in weapons to India, which is spending about $100 billion over 10 years to modernize its military.

The two nations are unlikely to go to war, but have no choice but to add to their military strength on the border as they gain clout, a senior Indian official with direct experience of Sino-Indian relations told Reuters.

“It is the currency of power,” he said. In the border negotiations, “we are ready to compromise, but up to a point.”