NEW YORK—Donald Trump was having a moment. Dressed in a tuxedo jacket and bow tie, the real estate mogul and former reality television star took the stage at last week’s New York State Republican Gala as the unlikely frontrunner for the GOP presidential nomination. Instead, as he scanned the crowd of nearly 1,000 Republican donors and party officials, including many from the Manhattan social orbit he’d been circling just outside of for decades, Trump sought a different kind of validation: one focusing on his business achievements.
