 At this summit, NATO leaders will emphasize that 23 of the 32 allies have reached the goal of investing a minimum 2% of GDP in their own militaries. But now with Russia's full-scale war on Ukraine, John Denny of the U.S. Army War College says that's no longer enough. The question remains whether our economies in the West can support this kind of spending. Unfortunately, too many of the major European allies have shown, at least so far, they don't have the economic strength to maintain this.