Anita Dunn and Bob Bauer: The Couple at the Center of Biden’s Inner Circle

Mr. Bauer and Ms. Dunn first crossed paths in 1984, when she consulted him on an election recount for a congressional campaign. They did not become close until several years later, when they were both working for the Democratic Senatorial Campaign Committee. She was the communications director, and he was counsel.

They married in 1993 and had a son; Mr. Bauer has three children from a previous marriage. The couple lives in Maryland with two cats, Oscar and Scoop. They privately joke that they have tried for years to get out of politics. It has not worked out that way.

Ms. Dunn and Mr. Bauer have an informal policy of never working for opposing candidates, and they have always pushed back on the idea that they are a team, friends say. Despite their tendency to travel from candidate to candidate together, allies insist that they are not quite a package deal.

And their tag-team style, while not exactly oppositional, is geared to define the legal and political parameters of a problem — often demonstrated through a disagreement.

They are married, but “you honestly wouldn’t know it in meetings,” where they are comfortable disagreeing with each other, said David Plouffe, who worked with both of them in the Obama White House.

Of Mr. Bauer, he said: “There’s a belief that he is by the book, but he’s also a problem solver, right? He doesn’t like to get close to lines, much less color outside of them, but he’s also very creative within the confines of the line.”

Once, earlier in their careers, Mr. Bauer criticized a communications plan his wife had just pitched for a Democratic Senate candidate so pointedly that a person in the room was stunned to later learn they were married. Ms. Dunn is known for the mantra “I want to push back,” when countering an opinion from her husband she considers to be wrong, friends say.