In the two and a half years since he resigned as New York’s governor, Andrew M. Cuomo has spent countless hours and millions of dollars to restore his image and vanquish his critics.

One of his primary targets is the state’s new ethics panel, which his lawyers argue was formed unconstitutionally and should be disbanded — a result that would plunge the enforcement of state ethics rules into chaos.

Mr. Cuomo won the fight’s first round, successfully persuading a State Supreme Court judge last year that the panel, the Commission on Ethics and Lobbying In Government, had been created in a way that violated New York’s Constitution.

After the commission appealed the ruling, the parties wound up in an appeals court in Albany, N.Y., on Friday for oral arguments.

Mr. Cuomo’s clash with the ethics panel goes back to the $5.1 million book deal he snagged for a 2020 memoir, “American Crisis: Leadership Lessons From the Covid-19 Pandemic.” The commission had been considering whether to compel him to forfeit the money when he sued.

Lawyers for Mr. Cuomo contend that the commission is unconstitutional in part because it employs a group of law school deans to vet political appointees for conflicts of interest, stripping the governor’s constitutional authority to oversee the panel. The model, created by Mr. Cuomo’s successor, Gov. Kathy Hochul, was created to increase the independence of the ethics commission, whose predecessor was dogged by allegations of corruption.