 So he's an expert at herding cats and building consensus, and that's exactly what he's going to have to do in NATO amongst 32 allies. Yeah, what are the biggest challenges that Rutte will face when he takes over NATO on October 1st? Timing is everything, and in two weeks' time, NATO has a historic and very important 75th anniversary summit in Washington, D.C., and NATO arguably faces the most difficult period since 1949. Hmm.