Donald Trump’s threat to leave NATO has one very big hurdle: approval from Congress.The president told The Telegraph Wednesday that he is weighing an exit from the 1949 compact, saying it is “beyond reconsideration.” He later clarified to Reuters that he planned to mention his dissatisfaction with NATO countries such as France, Poland, the U.K., and others refusing to join the war in Iran during a live address to the country Wednesday night.“I’ll be discussing my disgust with NATO,” Trump said....