For 74 years, the NATO has been America’s most important military alliance. Presidents of both parties have seen NATO as a force multiplier enhancing the influence of the United States by uniting countries on both sides of the Atlantic in a vow to defend one another.Donald Trump has made it clear that he sees NATO as a drain on U.S. resources by freeloaders. He has held that view for at least a quarter-century.In his 2000 book, “The America We Deserve,” Trump wrote that “pulling back from Europe would save this country millions of dollars annually.” As president, he repeatedly threatened...