The future of collective securityNato summit tests diplomacy and highlights the need for a common defence strategyCrisis, what crisis? The US needs Nato as much as everQuitting Europe would see Washington deliver to Beijing its most important strategic ambitionHow to fix NatoEmmanuel Macron’s doubts about the alliance deserve a serious responseTrump, Obama and their battle with the ‘blob’The Nato summit underlines a surprising continuity in US foreign policyA grand bargain for Europe might yet be possibleSecurity and climate change will be high on Ursula von der Leyen’s list of prioritiesNato needs to reassert its common purposeThe leaders of the western alliance should restore mutual trustThe west has a choice: back Ukraine or improve relations with RussiaVladimir Putin’s support for secessionist rebels has backfiredMore from this SeriesLetter: Britain should reconsider its costly and futile military presenceFrom Richard Reeve, London, UKDonald Trump brands Justin Trudeau 'two-faced'US president attacks Canadian leader after apparent mockery at Nato summit