“It’s a real cloud of a day for this family, and the election is a way to look at memory — Benjamin’s memory having faded, yes, but also the fading memories of Americans who so easily forget the disappointing things that Obama and Romney have said this year,” said Mr. Nelson, who is 62.

The fourth Apple play, which he has not started writing, will be set against the 50th anniversary of the Kennedy assassination on Nov. 22, 2013. Mr. Nelson, who lives and works in Rhinebeck, is also directing the plays, and the same five actors have been in all the productions so far. (A sixth character, the boyfriend of one of the siblings, was cut from “Sorry” because the actor had a scheduling conflict.)

Ben Brantley, in his review of last year’s “Sweet and Sad” in The New York Times, praised it as “soul-stirring” and went on to pinpoint the delicate task that Mr. Nelson had set for himself with the Apple plays. “One of Mr. Nelson’s points with this series is how world events are refracted and reflecting in our own living and dining rooms in ways we’re not always aware of,” he wrote.

If family dramas usually involve characters throwing fits in those living and dining rooms, Mr. Nelson sidesteps melodrama to render revelations in quieter moments, even silences. One wordless exchange in “Sorry” comes when Uncle Benjamin, fading into dementia, gently holds and kisses the hand of his niece and caregiver, Barbara, with whom he had been angry earlier. That reconciliation has nothing to do with the Obama-Romney race, but it points up what truly matters to people: making peace with a loved one, not who wins Ohio.

Mr. Nelson, the author of some 50 plays, adaptations and musical librettos, began writing the Apple plays on a commission for the Public Theater. The initial aim was to portray characters who were as confused as anyone in the audience about issues with real immediacy — in the case of “Hopey Changey,” the state of progressive Democratic politics in 2010 as voters (both in the audience and, ostensibly, in the play) were going to the polls.

The plays are all set in Barbara and Benjamin’s home in Rhinebeck — a house that actually exists on Center Street in that Hudson Valley town and that Mr. Nelson chose when he was first starting to imagine the Apple family. And while the Apples themselves aren’t based on anyone he knows there, aspects of their personalities and biographies came from conversations with a small group of friends Mr. Nelson and his wife, Cynthia, invite over most Saturday nights for dinners of pizza or Indian food.