WASHINGTON – As NATO leaders prepare for a pivotal July 7-8 summit in Ankara amid Russia's war against Ukraine and renewed tensions in the Middle East, former US Ambassador to the Organization for Security and Cooperation in Europe (OSCE) James Gilmore says the alliance is undergoing a difficult but ultimately strengthening transformation rather than entering a period of decline.In an interview with RFE/RL, Gilmore, who served during President Donald Trump's first administration, argues Trump's pressure on European allies has accelerated long-overdue changes, insists Ukraine "cannot be allowed to fail," and says NATO remains indispensable to both European security and US national interests.RFE/RL: We're heading into what many describe as one of the most consequential NATO summits in years. President Trump has repeatedly called for a more balanced transatlantic partnership. From the US perspective, what would demonstrate that this relationship is becoming more equal -- not only financially, but strategically?James Gilmore: First of all, I'm very optimistic about the future of NATO and about the future of the world. It is true that there's a reset going on. Let's look at NATO's situation realistically. The alliance has grown through the accession of Finland and Sweden. When I served as ambassador -- and even earlier, when I was a soldier stationed in Germany -- nobody ever thought Sweden and Finland would join NATO.