The Nato summit was already shaping up to be less about military strategy than managing one man. According to reports, European allies arrived in Ankara determined to avoid a spat with US President Donald Trump, with European leaders focusing on demonstrating higher defence spending and stronger military commitments rather than reopening old disputes.

Defence spending, Ukraine and the Iran conflict will dominate the Ankara meeting

Beyond the probable show of unity at this week's summit in Ankara, there could be trouble ahead for the alliance if the US continues down an isolationist path