ATLANTIC CITY — In this fading hub of spinning fortunes and Northeastern excess, Hillary Clinton found little occasion for subtlety.

Behind her was the barely visible outline of a Trump Plaza casino sign. Above her, dozens of once-gleaming light bulbs, now dark.

And looking back at her on Wednesday, in the company of sea gulls and a handful of protesters baking in the midday heat, hundreds of locals familiar with the handiwork of Donald J. Trump filled a patch of this historic boardwalk that has, in recent years, had too few customers.

“People get hurt,” Mrs. Clinton said, speaking briefly in bumper sticker, “and Donald gets paid.”

Mrs. Clinton had come to perhaps the foremost site of Mr. Trump’s checkered business history to make the case that his appeals to working people belie his history of hurting them.