Carnegie Europe’s Erik Brattberg sees challenges ahead for the transatlantic relationship:

• Afghanistan: Donald Trump’s administration is preparing for a troop surge in the country (despite the president’s own doubts). European support is lukewarm at best. Germany, where the pacifist Green party is probably going to be part of the next coalition government, could prove especially problematic.
• Iran: Trump is determined to blow up the 2015 nuclear deal. Europe — together with China and Russia — wants to keep it in place.
• North Korea: Europe plays little role in this crisis, but public opinion blames Trump for escalating it. Leaders will be hard-pressed to back him up, even if North Korea is in the wrong.

There have been other schisms. Trump pulled the United States out the Paris climate accord and his protectionism has killed any hope of completing a transatlantic free-trade agreement.

Europe’s response is to double down on multilateralism:

• With Britain on the way out, defense cooperation inside the EU is no longer taboo. Western European countries have already agreed to jointly develop a new generation of fighter jets and procure an alternative to American drones.
• Germany is now open to French proposals for closer eurozone integration and harmonizing corporate tax rates to boost the single market.
• The EU is pushing free-trade deals with Japan and Mexico, two nations that were left in the cold by Trump’s withdrawal from the Trans Pacific Partnership.