Citizen diplomacy

Over the decades, the two cities have worked together to bolster ties. In 2013, Washington DC joined the Beijing-proposed World Tourism Cities Federation. A year later, China Airlines launched a direct air route between the two capitals.

Mayor Muriel Bowser of Washington DC, in her remarks, recalled a number of "successes" of the sisterhood, including the refurbishing of the Friendship Arch, a well-known landmark in the US capital's Chinatown neighborhood, the establishment of a DC office in Beijing, and collaboration between artists and schools in both cities.

Bilateral sister-city relationships have flourished between China and the United States. The two countries now enjoy 277 twinned pairings at different levels, and momentum remains strong, Sister City International President Roger-Mark De Souza told Xinhua in an interview earlier this year.

"There are a lot of opportunities because China is so large, it's such a large population, a lot is happening," De Souza said, noting that there's equal enthusiasm on both sides.

"For 40 years, friendship and cooperation have been a keynote of China-US relations. There is a lasting driving force for our relations to move forward," said Cui.

"The sister-city relationship is an important way to enhance the people's friendship and subnational cooperation. It provides a strong momentum for bilateral relations between the two countries," he added.

Kalicki said he believes the relationship between Beijing and Washington DC is an important part of ties between China and the United States, while expressing hope for stronger people-to-people exchanges in the future.

Two-way learning

The relationship between China and the United States is facing challenges from the ongoing trade dispute initiated by the current US administration. However, enthusiasm for subnational exchanges and cooperation at different levels and in various areas between the two sides remain robust.

On the sidelines of the Utah-China Trade and Investment Forum in Salt Lake City earlier this year, former Utah House speaker Greg Hughes told Xinhua that the western US state needs partners in China.