Introduction

      As the end of the 20th century approached, Americans were gripped by anxiety about a looming, inescapable danger. Terrorism? War? No, a computer problem that threatened severe and widespread disruption of electronic networks around the world. Y2K, as it was known, raised the prospect that at the dawn of the new millennium, we would all be huddling anxiously in the dark. People bought gallons of bottled water, stockpiled matches, candles and batteries, made sure their cars had full tanks of gas, and loaded pantries with imperishable foods.

      It all turned out to be a phantom threat. As midnight struck in one country after another in time zones east of us, Americans breathed sighs of relief, chilled the champagne, and got ready to toast the New Year. We had averted catastrophe. It was a promising omen for the 21st century. It was also a deceptive one.

      The 1990s were, by most standards, good years. Looking back on the bitter political wars between President Bill Clinton and Republicans in Congress, which led to his impeachment, it’s hard to figure out what charged the furies. The economy was in the midst of the longest peacetime expansion since World War II, with low inflation, a booming stock market and an unemployment rate once considered unattainably low. Things went humming along for so long that in 1998, The Economist dared to ask, “Has the business cycle finally been conquered?”

      The crime rate, which had hit a blood-curdling peak early in the decade, was headed downward. Welfare reform was a success that, combined with a vigorous economy, would transform the culture of poverty and lift the underclass into self-reliance.

      The Cold War was over, and Russia, along with its former satellites in Eastern Europe, was breathing free air. We were the only superpower on earth. The spread of democracy around the world heralded a new age. After the first war with Iraq, which ended in a clean triumph, U.S. military ventures were few and modest — Somalia, Bosnia, Kosovo, Haiti. The battle of Mogadishu, the subject of the book and movie “Black Hawk Down,” was our idea of a colossal military debacle.

      The threat of a nuclear exchange between hostile superpowers had vanished. Terrorism was a low-level irritant that rarely intruded into mass consciousness. When George W. Bush was inaugurated president in 2001, The Onion headline read, “Our long national nightmare of peace and prosperity is over.” Seriously, we might have asked, what could go wrong?

      A lot, it turned out. On January 1, 2000, we didn’t imagine the surprises that lay in store. The first was the 2000 presidential election, in which George W. Bush, who came in second in the popular vote, won anyway — with an unprecedented assist from the Supreme Court. His inaugural motorcade was met by demonstrations, chants of “Hail to the Thief” and airborne eggs. Less than nine months later, operatives of a radical Islamic group called al-Qaida hijacked airliners and crashed them into the twin towers of the World Trade Center and the Pentagon, the worst terrorist attack in American history.

      Soon our troops were fighting in Afghanistan, which had provided refuge to Osama bin Laden as he plotted against us, and before long, the Bush administration had set out on the path to invading Iraq. Neither war went as expected, and both lasted far longer and cost far more American lives than anyone expected.

      So much for peace. Prosperity? It stumbled in the mild recession of 2001, only to collapse in the Great Recession of 2007, the worst since the days of Herbert Hoover. As of this writing, the economy has yet to regain its previous vigor, and the proportion of working-age Americans with jobs fell to the lowest level since the 1970s. We still have troops in Afghanistan, and U.S. forces are carrying out attacks in Iraq (and Syria) against an enemy that our occupation