In 2012, President Obama made a speech highlighting a specific goal of his foreign policy: a “pivot” to East Asia, where his administration would overturn the Bush-era paradigm of a Middle Eastern focus.

This pivot would include “strengthening bilateral security alliances, forging a broad-based military presence, and advancing democracy and human rights.”

Unfortunately, a series of foreign crises turned this pivot on its head, and Obama was forced to focus on Iran’s nuclear program, civil wars in Syria and Ukraine, and the threat of such terrorist groups as ISIS. Despite all this, the East Asia “pivot” has not been forgotten.

According to Reuters, U.S. Secretary of State John Kerry will ensure China is aware of the United State’s intentions for the region after a visit to Beijing this weekend. That includes making sure that the South China Sea, a contested trade route of strategic importance, is kept open to navigation for all countries in the region.

The struggle over the South China Sea has turned into a sort of Cold War for China and others in East Asia, namely the Philippines and Vietnam. Trade routes among these nations often crisscross in the sea, one of the world’s busiest shipping corridors. Trade that passes through the South China Sea is valued at $5 trillion. And in recent years, China has asserted a greater presence in the area by using “artificial islands,” essentially filling shallow waters around a chain of islands with sand, cement, wood, and steel and creating an expansion of its territory. These actions are creating tension that could eventually result in open conflict.

It’s a scenario that the United States hopes to moderate. U.S. Defense Secretary Ash Carter has directed his staff to look at military options for the area, including placing naval ships and aircraft in operating range of China’s territorial waters to dissuade further expansion, according to the Wall Street Journal.

The news was not well-received in Beijing. “China will resolutely safeguard its own sovereignty. We call on the relevant parties to be cautious with their words and actions, and not take any risky or provocative actions,” China Foreign Ministry spokeswoman Hua Chunying was quoted in a news conference.

Of course, this is a blatant example of saying one thing and doing another. China’s expansion threatens the sovereignty of other nations as much as the U.S. efforts to step in threaten its own. Regardless, it seems a brief moment of cooperation between China and the U.S. (that resulted in a joint deal to cut carbon emission) has all but ended. The pivot to East Asia now seems to have taken on an adversarial tone.

This is a disappointing reality that the United States now must face. While cooperation between arguably the two greatest superpowers of the 21st century is still something to strive for, we mustn’t let China establish a regional hegemony that suppresses the rights of other sovereign nations.