W hen Israeli Prime Minister Benjamin Netanyahu arrived at Mar-a-Lago in late December, he had a surprise message for President Trump: Israel would begin weaning itself off U.S. military aid. At first, Trump was taken aback: The billions of dollars that Washington provides Israel each year, after all, have been a bedrock of America’s Middle East strategy for decades, and essential support for its closest regional ally. Trump, ever the wary transactionalist, ribbed the prime minister: Oh, and