They dug for revelations, extracting news nuggets — a rarity on a debate night — like Donald J. Trump’s admission that he had used a nearly billion-dollar loss to avoid paying federal income taxes for years.

They pressed for specifics, interrupting the candidates to demand concrete strategies for handling conflict in Syria and reforming the nation’s health care system.

And they posed blunt, provocative questions at a forum that typically feels more like public broadcasting than cable news: Had Mr. Trump ever sexually assaulted a woman? Did Hillary Clinton really believe that her use of a private email server was not “extremely careless”?

The duo overseeing Sunday’s presidential debate, Anderson Cooper of CNN and Martha Raddatz of ABC News, seemed to cast off the hand-wringing pressures on this year’s crop of moderators — Is fact-checking mandatory? Are interruptions O.K.? — and put themselves directly in the mix of a high-stakes encounter.