Brad Lander, a cerebral and unassuming city councilman from Brooklyn with a degree in anthropology, has abruptly become the sort of person who endlessly fascinates scholars of the modern metropolis: a power broker.
Allies greet him with mazel tovs and hugs. Supporters ask if he will run for mayor in 2021. An old friend, spotting him at a social gathering, bows deeply — a not entirely facetious acknowledgment of Mr. Lander’s new status as a kingmaker in City Hall.