The foreign-policy crises that will shape the Trump era will tug on these threads— history is dominated by crisis and discontinuity, not steadiness or incrementalism, after all.

1. Putin’s big gambit. For Vladimir Putin, Trump’s presidency offers the opportunity of his lifetime. Trump dislikes NATO, admires Putin, wants to appease Russia, and is at war with his own intelligence community. But Putin’s optimism must be tempered by his knowledge the window of opportunity will remain open for only a short time before slamming shut. Trump’s position is brittle. He could be impeached or tamed by the establishment. He has persuaded virtually no one of consequence to adopt his pro-Russia view. In fact, bruised by Russian interference, many Democrats and Republicans may very well decide they have a new reason to fight another Cold War.

Now, Putin must be wondering how to take advantage of the Trump window to achieve something that can’t be undone by his successors. Putin fancies himself the heir of Peter the Great—how can he transform the world? Nothing infuriates him more than a European security architecture that denies what he sees as Russia’s rightful place as a great power. Surely the most tantalizing prize would be to break NATO by demonstrating that its mutual security guarantee, Article 5, is meaningless.

The challenge for Moscow is to exploit Trump’s pro-Russian policy without humiliating him to the point that he turns on Putin. That’s no easy task. But it is within his grasp. We can expect a challenge where the onus will be on Trump to act. It would go against every fiber of his being—to credibly threaten to wage war on behalf of an ally against Russia. It could tear apart the western alliance, taking the Trump administration down with it.

2. Fighting an economic war with China. China was one of the few countries in the world to welcome Trump’s success. Its government detested Hillary Clinton and her team, welcomed Trump’s criticism of U.S. alliances, and believed he was a pragmatist who would cut a deal. Xi Jinping, the leader of China, must be feeling whiplash now. Trump and his team—specifically his trade advisors Robert Lighthizer and Peter Navarro, and strategist Steve Bannon—believe China is waging an economic war against the United States through currency manipulation, the use of state-owned enterprises, and limiting market access, and want to retaliate in kind. As Trump advisor Anthony Scaramucci told the World Economic Forum in Davos, Trump believes the United States can fight and win an economic war with China. The United States may be hurt by the aftermath, but China will be hurt more. And it will yield. Or so the argument goes.

A U.S.-China economic war would be a catastrophe for both countries, for Asia, and for the global economy. But it would be a crisis of Trump’s choosing. The Trump administration is willing to pull every lever and use every economic and geopolitical weapon, including Taiwan, to bludgeon China into submission. For Xi, this must look like an existential threat. Xi, of course, is not blameless. He has pioneered an economic nationalism that has stoked tensions. But Trump’s position will be widely—and correctly—viewed as reckless and counterproductive.