US President-elect Donald Trump faces the delicate question of how to deal with two of the world’s most powerful leaders as soon as he sits down in the oval office of the White House after his inauguration on January 20. His dealing with both Russia’s President Vladimir Putin and China’s President Xi Jinping will have tremendous influence over policy from eastern Europe to the middle east to Northeast Asia.

It’s hard to say which of these two confronts Trump with the more serious problem, but let’s start with Xi. Trump has promised to impose protective tariffs on China for what he sees as unfair practices that have given China a trade surplus with the U.S. of multi-billions of dollars over the years.

That tough campaign promise, though, runs smack into China’s bond with North Korea. Yes, the United States, after strenuous negotiations, managed to persuade China to sign on to highly strengthened sanctions against North Korea in retaliation for the North’s fifth nuclear test and numerous missile tests. No, China may not enforce sanctions as desired while maintaining its own close relations with North Korea. We have to assume that Xi would be even less likely to want to bear down on North Korea if the US were to carry out Trump’s threats of a tariff wall that would also deepen the confrontation all around the Chinese periphery, from the Indian Ocean to the South China Sea to the East China Sea.

It’s hard to believe that Trump, while engrossed in shifting US policy on domestic issues and carrying on with efforts to block illegal immigration across the southern border and tightly screen Muslims coming to the US, will want to face off right away with China. More likely, the US will hold out the possibility of barriers to Chinese imports while attempting to win concessions that will somehow reduce the imbalance. As this drama unfolds, we may expect relations between Trump and Xi to be quite uncertain.

The standoff with Russia is just as complicated. Trump seems to have formed a special friendship with Putin, and Rex Tillerson, whom he’s named as secretary of state, has had major dealings with Russia as Exxon boss. Both of them should be inclined to want to be warm and friendly with Putin, but other factors may upset US-Russian relations.

The most obvious is the cyber-espionage against which President Obama retaliated by expelling 35 Russian diplomats from the US, among other measures. Was Russia really trying to influence the US presidential election? Democrats are convinced the Russians, at Putin’s direction, wanted Trump to defeat Hillary Clinton, who might have taken a hard line on Russia had she won.

Trump dismisses such talk as an absurd attempt at rationalizing her defeat and would like to give Russia the benefit of any doubt. That’s why, of course, Putin did not respond in kind to the expulsion of Russian diplomats to the US, preferring to do nothing while hoping Trump will be inclined to smooth over differences.

Trump may equivocate on the cyber-espionage issue pending advice and evidence from US intelligence agencies but will probably want to move on even if he’s convinced the Russians were up to something. What to do about Russia will be more difficult, however, as the spotlight shifts to countries in which the US and Russia share quite differing interests. Puitin’s Russia has inflamed tensions in eastern Europe by taking over portions of Ukraine beginning with Crimea. Russia and Iran both supported Syrian President Bashar al-Assad in a terrible campaign in which hundreds of thousands of people lost their lives.

Heart-rending images from the city of Aleppo showed the agony of a war in which the US chose not to intervene. The U.S. and Russia both oppose the Islamic State of Syria and Iraq, deep differences make cooperation all but impossible. Differences are most acute over Iran, which Russia sees as almost an ally and Israel views as a mortal enemy. The US remains totally committed to Israel, the recipient annually of US$3.2 billion in aid, soon to rise to US$3.8 billion, despite Israeli Prime Minister Benjamin Netanyahu’s rage over U.S. refusal to veto the UN Security Council resolution excoriating Israel for building settlements on Palestinian land.

And then there’s North Korea. Putin is deeply interested in enlarging on ties with North Korea partly to compete with China. Russia exports natural gas to the North, and traffic moves by railroad from Russia across the Tumen River to the North Korean economic complex at Rason. Like China, Russia may not be interested in enforcing sanctions on North Korea despite having voted for sanction resolutions imposed by the UN Security Council.

Putin’s response will be attuned to relations with the US in the Middle East and Europe. Trump and Tillerson may find Putin cold and calculating despite previous friendly encounters. It will be exciting to see how well, or badly, Trump gets along with these two giants, China and Russia, both of which are sure to be looking for weaknesses in the US global network of military and diplomatic alliances.