Ukrainian President Volodymyr Zelensky on Thursday urged NATO countries supplying his forces with arms to allow the weapons to be used to strike targets deeper into Russian territory. Some NATO countries, such as Lithuania, are giving Ukraine arms without restrictions, other than the limits of international law. But others impose strict rules on how they can be used, especially when it comes to striking targets in Russia. For example, the United States only allows strikes on the Russian side of the border in order for Ukraine to return fire in the vicinity of Kharkiv. Italy, meanwhile, only al…