AT the turn of the 20th century, toward the end of a brutal and surprisingly difficult victory in the Second Boer War, the people of Britain began to contemplate the possibility that theirs was a nation in decline. They worried that London’s big financial sector was draining resources from the industrial economy and wondered whether Britain’s schools were inadequate. In 1905, a new book  a fictional history, set in the year 2005  appeared under the title, “The Decline and Fall of the British Empire.”

The crisis of confidence led to a sharp political reaction. In the 1906 election, the Liberals ousted the Conservatives in a landslide and ushered in an era of reform. But it did not stave off a slide from economic or political prominence. Within four decades, a much larger country, across an ocean to the west, would clearly supplant Britain as the world’s dominant power.

The United States of today and Britain of 1905 are certainly more different than they are similar. Yet the financial shocks of the past several weeks  coming on top of an already weak economy and an unpopular war  have created their own crisis of national confidence.

On Friday, as the stock market finished one of its worst weeks by falling yet again, to roughly half of its level just one year ago, the Gallup Poll reported that Americans were substantially more pessimistic about the economy than they have been in more than two decades of polling. Nearly 60 percent say the economy is in poor shape, and 90 percent say it’s still getting worse.