Challenges of the 21st Century

By the end of this lesson, students will be able to:

• Account for the immediate and long-run effects of the September 11, 2001 attacks on American foreign policy, federal surveillance authority, and the relationship between citizens and the federal government.
• Trace the global War on Terror through the Afghanistan invasion of 2001, the Iraq War of 2003 to 2011, the Guantanamo Bay detention facility, and the long withdrawal from Afghanistan in 2021.
• Explain the causes and consequences of the 2008 financial crisis, including the Troubled Asset Relief Program, the rescue of General Motors and Chrysler, the Affordable Care Act of 2010, and the political polarization that followed.
• Account for the major social and constitutional shifts of the period, including marriage equality in Obergefell v. Hodges (2015), the Black Lives Matter movement that emerged after 2013, and the COVID-19 pandemic that produced more than one million United States deaths.
• Use Skill 2.C (Sourcing and Situation) to analyze how the historical situation, intended audience, and purpose of a post-2001 government document shape its meaning, and to support an argument with at least one twenty-first century primary source.

The morning of September 11, 2001 is the hinge that turns the decade after the Cold War into the era of the War on Terror. At 8:46 a.m. American Airlines Flight 11 struck the North Tower of the World Trade Center in Lower Manhattan. Seventeen minutes later United Airlines Flight 175 struck the South Tower. American Airlines Flight 77 hit the western wall of the Pentagon at 9:37 a.m., and at 10:03 a.m. United Airlines Flight 93, taken back from its hijackers by passengers who had heard about the New York attacks by phone, crashed into a field in Shanksville, Pennsylvania. Both World Trade Center towers collapsed before noon. Two thousand nine hundred seventy-seven people died, including the nineteen al-Qaeda hijackers, the largest single-day loss of American life on American soil since the Civil War. The 9/11 Commission, established by Congress in late 2002, traced the plot to Osama bin Laden, to the al-Qaeda safe haven inside Taliban-ruled Afghanistan, and to a long failure of imagination across the federal intelligence community (KC-9.3.II.A).

The federal response was rapid and lasting. On September 18, 2001, Congress passed the Authorization for Use of Military Force, a one-page joint resolution that authorized the president to use force against any nation, organization, or person determined to have aided the September 11 attacks. The resolution remained on the books for more than two decades and supplied the legal foundation for military operations across Afghanistan, Iraq, Yemen, Somalia, and beyond. On October 7, 2001, United States and allied forces began the invasion of Afghanistan, removing the Taliban government within weeks but failing to capture bin Laden. The Afghanistan war would not formally end until the chaotic American withdrawal of August 2021, making it the longest war in United States history. On October 26, 2001, President George W. Bush signed the USA PATRIOT Act, a 342-page statute that lowered the legal wall between intelligence and law enforcement, broadened the Foreign Intelligence Surveillance Act, authorized roving wiretaps, and expanded the federal government's authority to collect bulk records on Americans. The act became the canonical example of the post-September 11 trade-off between security and civil liberties, a debate that intensified after Edward Snowden's 2013 disclosures revealed the scope of the National Security Agency's bulk-collection programs (KC-9.3.II.A).

The Iraq War followed in 2003. The Bush administration argued that the regime of Saddam Hussein possessed weapons of mass destruction and supported transnational terrorism. United States and coalition forces invaded on March 19, 2003, captured Baghdad within three weeks, and removed the Hussein government. The weapons of mass destruction case, however, did not hold up. The Iraq Survey Group's final report in 2004 concluded that Iraq had ended its prohibited weapons programs in 1991. By the time American combat forces withdrew at the end of 2011, more than 4,400 American service members had died in Iraq and an estimated several hundred thousand Iraqis had been killed in the war and the insurgency that followed. The Guantanamo Bay detention facility, opened in early 2002 to hold detainees from Afghanistan and the broader War on Terror outside the federal court system, became a symbol of the legal innovations of the post-9/11 era and the subject of a series of Supreme Court rulings, including Hamdi v. Rumsfeld (2004) and Boumediene v. Bush (2008), that pushed back against unreviewed executive detention (KC-9.3.II.A).

Four years after the September 11 attacks, the federal response to a domestic disaster eroded public confidence in a different way. Hurricane Katrina made landfall on the Gulf Coast on August 29, 2005, breached the levee system that protected New Orleans, and flooded roughly eighty percent of the city. More than 1,800 people died across Louisiana, Mississippi, and Alabama, and tens of thousands of residents, disproportionately Black and poor, were stranded inside the city for days. The slow Federal Emergency Management Agency response, the visible inadequacy of the federal levee system, and the televised images of suffering inside the New Orleans Superdome turned Katrina into a federal failure that lingered well past the storm. Katrina foreshadowed a recurring twenty-first century pattern: extreme weather amplified by a warming climate, federal infrastructure that had not been built for the new conditions, and a political response that fell along racial and partisan lines (KC-9.3.II.D).

The financial system broke down three years later. The 2008 financial crisis began with the collapse of the subprime mortgage market in 2007, gathered force with the failure of Bear Stearns in March 2008, and broke open with the bankruptcy of Lehman Brothers on September 15, 2008. Within weeks Congress passed the seven hundred billion dollar Troubled Asset Relief Program, the Federal Reserve opened emergency lending facilities to a long list of non-bank institutions, and the federal government took ownership stakes in General Motors and Chrysler to prevent the collapse of the American auto industry. The Great Recession that followed produced the highest unemployment rate since 1982, wiped out roughly nineteen trillion dollars in household wealth, and accelerated foreclosures across communities that had relied on subprime lending. The political response came in two waves. Inside the Democratic Party the crisis produced the Affordable Care Act of 2010, the largest expansion of federal health insurance since Medicare and Medicaid in 1965. Inside the Republican Party it produced the Tea Party movement, which campaigned against the bailouts, the federal deficit, and the Affordable Care Act and reshaped the party from the right (KC-9.3.II.B, KC-9.3.II.C).

The Obama presidency from 2009 to 2017 sat on top of all of these inheritances. Obama oversaw the raid on Osama bin Laden's compound in Abbottabad, Pakistan in May 2011, ending a ten-year manhunt; signed the Affordable Care Act in 2010; and drew the United States toward the Trans-Pacific Partnership, a twelve-nation trade agreement that became politically untenable by 2016. Underneath the federal politics a generational racial reckoning gathered. The killing of Trayvon Martin in Florida in February 2012 and the acquittal of George Zimmerman in 2013 produced the Black Lives Matter movement, which expanded after the 2014 deaths of Michael Brown in Ferguson, Missouri and Eric Garner in Staten Island, New York, and again after the 2020 killing of George Floyd in Minneapolis (KC-9.3.II.B). On the constitutional side, the Supreme Court's 2015 decision in Obergefell v. Hodges recognized a constitutional right to same-sex marriage, completing the long expansion of LGBTQ civil rights that had begun with Lawrence v. Texas in 2003 (KC-9.3.II.C).

The Trump presidency from 2017 to 2021 moved federal policy in a new direction. The Tax Cuts and Jobs Act of 2017 cut the federal corporate tax rate from thirty-five percent to twenty-one percent, the largest corporate rate reduction in modern American history. The administration tightened immigration enforcement, reduced refugee admissions, and pursued a southern border wall. In early 2020 the COVID-19 pandemic began. The novel coronavirus was first identified in Wuhan, China in late 2019, and by March 2020 it had reached community transmission across the United States. Federal, state, and local governments imposed school closures, business restrictions, and stay-at-home orders. The pandemic produced more than one million United States deaths by 2023, the largest mass-casualty event in American history outside the Civil War, and an emergency federal response that included the CARES Act of March 2020, the development and rollout of mRNA vaccines under Operation Warp Speed, and the largest expansion of federal cash transfers since the New Deal. The 2020 election produced a Democratic victory, and on January 6, 2021, supporters of President Trump attacked the United States Capitol in an attempt to disrupt the certification of the electoral count, an event with no clear precedent in American constitutional history (KC-9.3.II.B, KC-9.3.II.D).

Two long-horizon issues sit underneath all of these events. The first is climate change. By the 2010s the warming of the global atmosphere was no longer a contested scientific claim but a recurring political one, with debates running through the 2017 withdrawal from and 2021 return to the Paris Climate Agreement, the long question of fossil fuel subsidies, and the increasing cost of federal disaster response. The second is political polarization. The gap between the median Democratic voter and the median Republican voter has widened steadily since the 1990s, and by the early 2020s the two parties disagreed not only about policy but about basic facts. The challenges of the twenty-first century are not finished. Period 9 closes whenever the next CED revision draws a new line.

A lesson on twenty-first century challenges works best when it samples sources that span the political, foreign-policy, and constitutional fault lines of the era. The four excerpts below cover the immediate aftermath of September 11, the legislative response to the attacks, the forensic record of the plot, and the constitutional turn toward marriage equality. Government documents and Supreme Court opinions are the safest classroom sources for this period because contemporary journalism and photography remain under copyright.

1. (Causation) Trace the causal chain that runs from the morning of September 11, 2001 through the Authorization for Use of Military Force, the USA PATRIOT Act, and the invasions of Afghanistan and Iraq. At which step in the chain do you think a different decision could have produced a different outcome, and why?
2. (Continuity and Change) The USA PATRIOT Act expanded federal surveillance authority during a national-security emergency. Identify two earlier moments in American history when wartime expanded federal authority over civil liberties (for example, the Sedition Act of 1798, Lincoln's suspension of habeas corpus, or the Smith Act of 1940). What does the comparison reveal about continuity and change in the relationship between war and civil liberties?
3. (Comparison) Compare the federal response to Hurricane Katrina in 2005 with the federal response to the COVID-19 pandemic that began in 2020. What does the comparison reveal about the federal government's capacity to respond to large-scale crises in the twenty-first century?
4. (Causation) Account for the political polarization that followed the 2008 financial crisis. How did the Troubled Asset Relief Program, the Affordable Care Act, and the rise of the Tea Party and Black Lives Matter movements together produce the politics of the late 2010s and early 2020s?
5. (Continuity and Change) The Obergefell v. Hodges decision of 2015 recognized a constitutional right to same-sex marriage. Identify one earlier expansion of civil rights that follows a similar pattern (for example, Brown v. Board of Education in 1954 or Loving v. Virginia in 1967) and one significant difference. What does the comparison reveal about how civil rights have expanded across the twentieth and twenty-first centuries?

Draft alignment — pending educator review. AP USH codes correspond to the official College Board Course and Exam Description (Effective Fall 2023, Version 1). Statements below are paraphrased in the CountryReports voice; refer to the College Board's published CED for verbatim wording.