After meeting with China¡¯s top diplomat in Malaysia last summer, U.S. Secretary of State Marco Rubio uttered a line that made few waves at the time but would later help pave the way for an abrupt change.

The United States and China, Rubio said, had an ¡°opportunity here to achieve some strategic stability¡± and find areas of cooperation. He used the phrase again in February while talking about China in the Caribbean, also to little notice.

Chinese officials picked up on Rubio¡¯s remarks and suggested to their U.S. counterparts even rosier language to describe ties between the two nations, according to two people with knowledge of the previously unreported diplomacy.