AT&T Chief Says It Made a ‘Big Mistake’ Hiring Michael Cohen

For AT&T, the disclosure of its ties to Mr. Cohen comes at a critical moment. The company is defending its merger with Time Warner in federal court against the Justice Department’s efforts to block the deal.

It is unclear what services Mr. Cohen provided. Mr. Stephenson insisted in his memo that “everything we did was done according to the law and entirely legitimate” and that Mr. Cohen did not do any lobbying on behalf of AT&T. Nonetheless, Mr. Stephenson added, retaining Mr. Cohen “was a serious misjudgment.”

Time Warner was not aware of AT&T’s contract with Mr. Cohen, according to a person familiar with the company’s thinking. Within Time Warner this week, officials were surprised to learn about the contract with Essential Consultants.

Mr. Cohen did not respond to an interview request.

Many large corporations consider such strategic advice to be part of their government affairs program, complementing their overt lobbying efforts. AT&T’s contract with Mr. Cohen, for instance, called for him to advise the company on “corporate tax reform and the acquisition,” according to documents first obtained by The Washington Post.

But Mr. Stephenson said that with Mr. Cohen, “our Washington, D.C., team’s vetting process clearly failed, and I take responsibility for that.”

Mr. Stephenson said that Mr. Quinn, 57, who had led the Washington team, had decided to retire. But according to a person familiar with AT&T’s thinking, who was not authorized to speak publicly about the decision, he was pressured to leave because of the revelations of AT&T’s contract with Mr. Cohen.

Mr. Quinn began working at AT&T in the 1980s and is well connected in the political circles of both parties. But he, and the rest of the company, was surprised by the election results and had few connections to Mr. Trump’s circles.