"[NATO] feels more highly relevant to contemporary challenges—more so than it has been since the end of the Cold War," said Kathleen McInnis, a NATO and coalition warfare expert at Chatham House, a London-based policy institute. She explained that despite geopolitical worries that pervade much of Europe, many member states have struggled to make increased defense spending politically palatable.
Problems with military funding have plagued the alliance for years, but they are becoming more serious as threats on the periphery of Europe grow.
"The geopolitical reality surrounding Europe and surrounding NATO is changing so much, it's not clear that NATO members can waffle their way through this again," McInnis explained.
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An agreement struck during the NATO summit in Wales last September reaffirmed members' commitment to spend at least 2 percent of their gross domestic product on defense. The declaration said that NATO countries already meeting that spending level—a group that included only the United States, United Kingdom and Estonia—will continue to do so. And it said that nations under that 2 percent bar will halt spending declines and move toward the guideline within a decade.
Although the 2 percent level may seem arbitrary, it is "probably the absolute minimum modern countries can pay" in order to maintain adequate security, according to Anthony Cordesman, the Arleigh A. Burke Chair in Strategy at the Center for Strategic and International Studies.
But, as the European Leadership Network, a U.K.-based think tank, noted in a recent paper, at least six countries in NATO are expected to decrease their military spending: the U.K., Germany, Canada, Italy, Hungary and Bulgaria.