This week the generals persuaded Donald Trump to keep up the fight in Afghanistan. A frustrated US president agreed reluctantly. Time will tell whether his personality and politics can sustain a long-term commitment.

Half a year into his presidency, Mr Trump’s foreign policy has five distinctive features. The Trumpian approach differs from that of his predecessors in type, not just degree, and other countries around the world need to be aware of the dissonance with past conduct.

First, Mr Trump is transactional, not institutional. He views foreign policy like a dealmaker and does not care whether the outcomes fit America’s traditional practice of building systems that advance its interests and values. As a negotiator, Mr Trump will be periodically confrontational. He can be impulsive. He welcomes creating uncertainty, which he believes builds leverage. Mr Trump’s ego plays an exceptionally large role and so do personal — and even family — relations. He is the first president in my experience who does not believe the office is larger than himself.