Just as China and the United States are preparing for another Xi Jinping-Barack Obama summit next month, when the American president is scheduled to visit Beijing for the annual APEC leaders meeting, China is stepping up charges that Washington is secretly supporting student-led pro-democracy protests in Hong Kong.

Warnings against "foreign intervention" have been a constant theme in Chinese statements on the former British colony, but recent commentaries in the official media have raised the level of the rhetoric to such an extent as to make it appear as though the Hong Kong issue dominates the U.S.-China bilateral relationship.

Last Friday, the overseas edition of the official People's Daily newspaper published a front-page article accusing the National Endowment for Democracy, a nonprofit organization funded by the U.S. government, of involvement in the demonstrations in Hong Kong.