Saudi Deputy Crown Prince and Minister of Defense Mohammed bin Salman is representing his father at the Group of 20 summit in China on Sept. 4-5, another indication of the 31-year-old son's pivotal role in the kingdom. "Mr. Everything," as he is now called, is King Salman bin Abdul-Aziz Al Saud's most trusted adviser and most critical intermediary with other foreign leaders.

The prince began his trip to the G-20 with a brief stopover in Islamabad to meet with Prime Minister Nawaz Sharif and Chief of Army Staff Gen. Raheel Sharif. Saudi relations with Pakistan, a traditional ally, have been disrupted since Pakistan refused to join the Saudi-led coalition fighting in Yemen against the Houthi rebels. Pakistan's opposition to the war in Yemen enjoys widespread support in the country. The Pakistani parliament voted unanimously against sending troops to fight. But Pakistan still has a thousand advisers in the Saudi military and has participated in military exercises inside the kingdom in the last year.

The prince then made a bilateral visit to China, Saudi Arabia's largest oil market. Trade between the two peaked at almost $70 billion in 2014, before oil prices dropped. The Saudis want China to be a major investor in the prince's Saudi Vision 2030, an ambitious plan to reduce the kingdom's dependence on oil exports. He signed 15 agreements on economic and cultural ties with the Chinese during the visit. 

China is also the source of Saudi Arabia's intermediate-range ballistic missile force, the kingdom's strategic deterrent weapon that needs updating. The CSS2 missile system, provided by China in a secret deal negotiated by Prince Bandar bin Sultan, the Saudi ambassador to the United States in the mid-1980s, is aging. As defense minister, Mohammed bin Salman is interested in keeping the Saudi deterrent capabilities, especially against Iran, credible.