Wait for Royal Baby Lets a Nation Revel in Nostalgia

It is hard not to be struck by the frantic enthusiasm the monarchy still seems to inspire in 21st-century Britain.

Awaiting the birth of a child who will be third in line to the throne, commuters fill in know-your-royal-baby quizzes and shops sell “Born to Reign” onesies. The Museum of London has an exhibition called “A Royal Arrival,” displaying the embroidered infant skull cap once worn by Charles I and a nursing robe used by Queen Victoria.

This is a country where citizens are also known as “subjects,” where lawyers wear period-drama wigs in court and where by law, all swans, whales and sturgeons are the property of Her Majesty, Queen Elizabeth II.

But more than three-quarters of her majesty’s subjects are quite happy to keep in place the system of inherited privilege and power that in turn keeps her in Buckingham Palace, a proportion that has remained pretty stable over the decades.

According to the polling company Ipsos Mori, support for abolishing the monarchy stood at 18 percent in 1969, 18 percent in 1993, 19 percent in 2002 and 18 percent in 2011. This, the pollsters say, is probably the most stable trend they have ever measured.

At a time of economic hardship and falling confidence in other institutions, from Parliament to the financial sector to the media, this popularity is remarkable. “The royals are unbelievably resilient, and you have to give them credit for it,” said Maya Jasanoff, history professor at Harvard University and an expert on the British Empire.

Despite all the quirky anachronisms, the House of Windsor seems to have modernized its image just enough to maintain the population’s loyalty, Ms. Jasanoff said. The turbulent 1990s that saw Prince Charles and Princess Diana divorce, Diana killed in a car crash with her lover and a brief slump in the queen’s popularity as the palace struggled to manage this news flow might ultimately have helped to turn the royal family into something more human, more modern and “more normal,” Ms. Jasanoff said.

At the same time the monarchy provides to a nation troubled by austerity and bouts of nostalgia for a more glamorous past a sense of continuity, she said. The queen, who was crowned in 1953, is the most visible living link Britons have to World War II, a part of history that remains a defining moment for modern British identity.

“In America we’ve made the Constitution our source of stability,” Ms. Jasanoff said. “The monarchy is a source of stability.”