Federal law enforcement authorities have charged nearly 50 past or present Russian diplomats and their spouses in a $1.5 million Medicaid fraud scheme, an unusual twist in what has become a familiar criminal story line in New York. An F.B.I. investigation revealed “the systemic fraudulent submission of falsified applications for Medicaid benefits” by the diplomats and their spouses, according to a criminal complaint unsealed on Thursday in United States District Court in Manhattan. The diplomats and their spouses obtained the benefits for pregnancies, births and first-year-of-life medical needs, generally applying at the same New York hospital, which was not identified,...