WASHINGTON — In a week of White House tantrums and fast-food dinners, of canceled speeches and aborted congressional trips, it seemed fitting that Karen Pence, the wife of Vice President Mike Pence, announced that she was going back to her job as an elementary schoolteacher.

Washington these days resembles nothing so much as an unruly sandbox. As the shutdown drags on, septuagenarian politicians are squabbling like 7-year-olds, House freshmen staged a boisterous protest march to the empty office of the Senate majority leader and the president’s lawyer went spectacularly off the rails in a television interview. There did not seem to be an adult in sight.

“I am excited to be back in the classroom and doing what I love to do, which is to teach art,” Ms. Pence said in a statement about her new job, conjuring up a world of finger-painting and construction paper that seemed more civilized than the “Lord of the Flies” playground inhabited by her husband and his colleagues.

In that world, President Trump sent Speaker Nancy Pelosi a letter telling her that he was postponing her trip with a congressional delegation to visit American troops in Afghanistan. The president’s salvo came 24 hours after Ms. Pelosi informed Mr. Trump that because of the shutdown, she was rescinding her invitation to him to deliver a State of the Union address in the House chamber.