Perhaps, Europeans should be less worried about the direction of U.S. foreign policies under Trump than about the question how far Washington will be able to remain an effective geopolitical actor, at all. Trump’s victory’s main effect on international relations might be the U.S.’s reduced availability to the conduct of foreign affairs. The main repercussion of Trump’s surprising triumph may be that Washington will be too much consumed with internal conflicts to be as active in world politics as it used to be. Trump will have to rule against the background of a strong dislike of millions of Americans for him and his policies, and the so far unpredictable ways in which this dislike will express itself. (One cannot even exclude race riots or other turmoil.)
While it is unclear what this means for the functioning of the U.S. governmental apparatus including the military, it seems already clear that much of U.S. mass media, academia, arts scene and civil society will either only conditionally support or even actively fight Trump in the coming months and years. Even civil servants may find it difficult to properly do their job under President Trump, if he rules as erratic as his campaign behavior suggests he may. The main issue arising from this may not be zigzags in Washington’s foreign behavior, but rather its partial plain absence on the world political scenery during periods of domestic political infighting.
That means that the members and institutions of the European Union as well as other pro-Western countries and international organizations will probably have to take care much more of things than they have been used to do so far — as long as the US will be busy sorting out itself during the next four years (if no impeachment happens before).