5. Shinzo Abe. While much of the world was still recovering from the surprise of Donald Trump’s election in November, the Japanese prime minister got on a plane and became the first leader to meet with the president-elect. Why the urgency? For one, Abe invested significant domestic political capital in the TPP trade deal, which Trump has now torpedoed. For another, Trump has threatened to upset the balance of security in Asia by asking Japan and South Korea to pay more for the U.S. troop presence in those countries. Should economic or security trouble develop between China and the U.S., Japan may suffer side effects. Abe may have seen the Trump train coming, but whether he can change its course is another question.

4. Xi Jinping. For China, Hillary Clinton was at least a known quantity. Her famous speech there on women’s rights was decades ago. Trump, by contrast, seems deeply committed to keeping life in Beijing interesting. His administration’s latest move is to suggest that the U.S. will set up a blockade in the South China Sea to prevent China from asserting its territorial claims there. The U.S.-China relationship is large and multifaceted, and Trump can’t overthrow it with just a few words, even if they’re words spoken to the leader of Taiwan. But Trump has inserted himself into a delicate time in Chinese politics, as Xi Jinping prepares for a sensitive leadership transition in the fall. China’s government has pushed back hard to avoid a competition over who can be more nationalistic. America might not win that one.

3. Recep Tayyip Erdogan. In the wake of Turkey’s failed coup attempt last summer, the country’s president and his allies went to war with the American political establishment, accusing them of harboring their political opponent, Fetullah Gulen, and of shadowy involvement in the coup plot. Now, Trump has overthrown that establishment. Unlike the Democrats, the Trump administration has not batted an eye at Erdogan’s efforts to consolidate power in the presidency. And, for the moment, Turkey will have a freer hand to pursue its objectives in Syria, with less concern that the U.S. will empower its Kurdish opponents, as Clinton suggested she would. But the two won’t be able to avoid the elephant in the room indefinitely. How long can a U.S. president who explicitly divides the world’s Muslims into good and bad camps get along with an increasingly Islamist political leader?

2. Abdel Fattah el-Sisi. It is usually the American president who is accused of cozying up to foreign strongmen. In the case of Egypt’s president, it may be the other way around. Sisi has managed to push himself onto the U.S. president's agenda numerous times, including phone calls and an in-person meeting in September. Sisi’s drive to engage with Trump indicates the value he puts on American backing, tepid at best during the Obama administration. Sisi is facing crumbling support at home and a tense relationship Saudi Arabia, long a key ally. The two will find a useful adversary in the Muslim Brotherhood, which Sisi overthrew. Unlike Erdogan, Sisi will have no trouble playing Trump’s anti-Islam sentiments to his advantage.