The only thing that’s guaranteed about Trump’s foreign policy is its unpredictability

US President Donald Trump holds a news conference at the G20 summit in Osaka, Japan. Reuters/Kevin Lamarque

As US secretary of state Mike Pompeo visited India, and the G20 summit got under way in Japan on Friday, with President Donald Trump in attendance, there was increasing talk of Washington’s foreign policy incoherence.

Multiple geopolitical crises remain at varying levels of volatility, notably Iran, Venezuela and North…