The extent of the group’s financial problems has in some ways been masked by the foundation, which is sitting on more than $29 million that is counted as an asset on the N.R.A.’s books. Without it, the N.R.A. would have a negative net worth. The gun group said the money was largely an endowment set up for the N.R.A., but also encompassed reimbursements to the N.R.A. — for staff, supplies and rent — that had not yet been transferred.

Marcus Owens, a partner at Loeb & Loeb who served for a decade as director of the exempt organizations division of the Internal Revenue Service, said the sums moving to the N.R.A. from the foundation were “substantial related-party transactions,” and that “in normal times, they would attract regulatory attention from the I.R.S. and a state attorney general.”

Opponents see opportunity.

“Each day, there’s a new drip, drip, drip,” said John Feinblatt, president of Everytown for Gun Safety, a gun control group. “The N.R.A. is not a gun advocacy organization but a business that has been engaged in self-dealing, awarding contracts with little accountability to their friends, and it seems like a business run amok. It’s questionable whether they can play in 2020 the way they have in the past.”

Such groups showed unusual financial strength in the recent midterm elections. Take Nevada. For years, there had been a push to close loopholes in background checks related to private gun sales, culminating in a successful 2016 ballot initiative. Adam Laxalt, then the state’s Republican attorney general, appeared in a commercial opposing the measure, and was criticized when he later helped block it from going into effect.

When Mr. Laxalt ran for governor last year, he had the N.R.A.’s endorsement and A+ rating, and was fiercely opposed by gun control groups. He lost to Steve Sisolak, a Democrat who in February signed background check legislation into law.

“That is Exhibit 1 of their diminishing power, and their inability to do what they used to do,” Mr. Feinblatt said.

Mr. Rathner, the lobbyist and longtime N.R.A. board member, sees it differently. The organization’s members, he said, pay their dues “to protect them from anti-gun legislation and anti-gun policies, and quite frankly, we gave them a president who appointed two good Supreme Court justices and over 100 lower court judges to protect them for a generation or two. And we did that because that’s what our members expect us to do.”