Just a few years ago, it would have been practically unimaginable for Saudi Arabia, America’s longtime strategic partner, to join an economic and security organization led by China and Russia.

Last month, however, the kingdom approved a memorandum of understanding granting it the status of “dialogue partner” in the Shanghai Cooperation Organization — the first step toward full membership.

The SCO’s foundations were laid in the 1980s, when the Soviet Union and China were attempting to navigate tensions over their shared border. After the Soviet Union’s dissolution, two parties became five: the People’s Republic of China, the Russian Federation, Kazakhstan, Kyrgyzstan and Tajikistan. In 2001, the so-called Shanghai Five agreed that they should move beyond demarcation and demilitarization of borders to deepen regional cooperation — and the SCO was born.