The National Rifle Association's former second-in-command is breaking with the group's orthodoxy and calling for universal background checks and so-called red flag laws in a new book assailing the organization as more focused on money and internal intrigue than the Second Amendment, while thwarting constructive dialogue on gun violence.

The former executive, Joshua L. Powell, who was fired by the N.R.A. in January, reinforces the kind of criticism made of the organization by gun control groups and state regulators, but it is the first critical look at its recent history by such a high-ranking insider.

He describes the N.R.A.'s longtime chief executive, Wayne LaPierre, as a woefully inept manager, but also a skilled lobbyist with a deft touch at directing President Trump to support the group's objectives, and who repeatedly reeled in the president's flirtations with even modest gun control measures.