Explainer-What are the key challenges facing NATO?

By Lili BayerBRUSSELS, July 3 (Reuters) - NATO leaders gathering for a summit in Ankara on July 7-8 will discuss a host of challenges facing the alliance, from Europe taking on more responsibility for the continent’s security to boosting defence industrial production.Some officials worry the Iran war could overshadow the gathering, but hope leaders will remain focused on the alliance’s core business: defence and deterrence.Here is a look at the main challenges facing NATO in the months and years to come:KEEPING TRUMP IN