Historically there has been some contention between China and the US whenever the ghost of emissions past has raised its head. As China's economy has grown in recent years and its emissions consequently risen in tandem, the US had insisted that they be responsible for the greatest cuts.
Forces on both sides of the proposed bulk coal ports around Puget Sound are replaying a battle from the 1970s. The deciding factor then was a powerful senator. This time, as improbable as it seems, it might be CO2 emissions from China.