These days, the crisis is existential. Mr. Guardian is fighting for nothing less than the sovereignty of Atlantic City and its 40,000 residents, about 70 percent of whom are black or Hispanic.

He seems an unlikely defender of this relatively poor, predominantly Democratic and notoriously fractious constituency. He is gay, white and a Republican, and at 62, he is holding his first public office after spending much of his career as an executive with the Boy Scouts of America.

He has broached the idea of filing the first municipal bankruptcy in New Jersey since the Great Depression, a heretical notion in a city so dependent on free-spending visitors. But by many accounts, Mr. Guardian’s steady guidance through the stormy first two years of his tenure has enhanced his popularity.

“To be under that type of pressure and continue to put on your happy face and be a champion of the residents of this city, you can’t do nothing more than thank him,” said Ernest D. Coursey, an Atlantic County freeholder and a former deputy mayor of Atlantic City, who is a Democrat.