When Saudi Arabia’s Crown Prince Mohammed bin Salman arrives in Washington he will be greeted with great fanfare by Donald Trump — much as the US president was given a gilded welcome in Riyadh earlier this year. He will hope to leave with agreements on deepening long-standing ties between the world’s biggest economy and the largest oil exporter.

Yet, until recently, next week’s visit was at risk of being postponed, according to people with knowledge of the preparations.