Verified for the 2025 AP US History exam•Citation:
The early 21st century brought unprecedented challenges to the United States, from terrorism and war to economic crisis and climate concerns. Following the terrorist attacks of September 11, 2001, America launched military efforts against terrorism that led to lengthy conflicts in Afghanistan and Iraq. At home, Americans debated the balance between security and civil liberties, while also facing economic struggles and environmental issues. Despite these challenges, the United States maintained its position as the world's leading superpower.
On September 11, 2001, America experienced the deadliest attack on U.S. soil since Pearl Harbor. Al-Qaeda terrorists hijacked four commercial airplanes, crashing two into the World Trade Center towers in New York City, one into the Pentagon, and another—likely intended for the U.S. Capitol—crashed in a Pennsylvania field after passengers fought back against the hijackers.
The attacks killed nearly 3,000 people and profoundly changed American life and foreign policy. President George W. Bush declared a "War on Terror" and developed what became known as the Bush Doctrine, which included the controversial concept of "pre-emptive strikes" against potential threats.
Less than a month after 9/11, the United States invaded Afghanistan, where the Taliban government had sheltered al-Qaeda and Osama bin Laden. The initial invasion quickly toppled the Taliban regime, but securing and rebuilding the country proved much more difficult.
President | Afghanistan Policy | Troop Levels |
---|---|---|
Bush | Initial invasion and state-building | 25,000 by 2008 |
Obama | Troop surge then planned withdrawal | Peaked at 100,000 in 2011 |
Trump | Reduced presence, peace talks with Taliban | Reduced to 8,600 |
Biden | Complete withdrawal | Full withdrawal by August 2021 |
The war continued for nearly 20 years, costing over 2,400 American lives and trillions of dollars. In May 2011, U.S. special forces finally killed Osama bin Laden in a raid on his compound in Pakistan. Despite this victory, the war continued until the U.S. withdrawal in 2021, which resulted in the Taliban quickly regaining control of the country.
In 2003, the Bush administration launched a controversial invasion of Iraq based on claims that Iraqi dictator Saddam Hussein possessed weapons of mass destruction (WMDs) and had connections to terrorism. These claims later proved false, making the war highly controversial both internationally and domestically.
The Iraq War resulted in over 4,400 U.S. military deaths and hundreds of thousands of Iraqi civilian casualties. The war's total cost exceeded $2 trillion and contributed to regional instability that continued long after U.S. combat operations ended.
After 9/11, the United States greatly expanded its security and surveillance capabilities to prevent future attacks. These changes sparked ongoing debates about the proper balance between security and civil liberties in a democratic society.
The PATRIOT Act, passed just weeks after 9/11, gave the government expanded powers to monitor communications, access records, and detain suspected terrorists. While many Americans accepted these measures as necessary for security, others worried about government overreach and threats to privacy.
As years passed without another major attack on U.S. soil, criticism of these security measures grew. In 2013, Edward Snowden leaked classified information revealing the extent of NSA surveillance programs, further intensifying debates about privacy and security.
In 2008, the United States faced its worst economic crisis since the Great Depression. The housing market collapsed after years of risky lending practices, triggering a financial crisis that spread globally.
The crisis began with the housing bubble burst. Banks had been making risky subprime mortgage loans and packaging them into complex financial products. When housing prices fell, many homeowners defaulted on their loans, causing massive losses for banks and investors. This led to a credit freeze where banks stopped lending, bringing much of the economy to a halt.
Economic Indicator | Pre-Crisis (2007) | Crisis Peak | Recovery (2015) |
---|---|---|---|
Unemployment Rate | 4.6% | 10.0% (2009) | 5.3% |
Dow Jones Average | 14,000 | 6,547 (March 2009) | 18,000 |
Housing Prices | Peak | -33% from peak | Still below peak |
Federal Deficit | $161 billion | $1.4 trillion (2009) | $438 billion |
The Bush and Obama administrations took extraordinary measures to prevent economic collapse, including government bailouts, stimulus spending, and financial reforms.
The Economic Stabilization Act of 2008 created a $700 billion Troubled Asset Relief Program (TARP) to purchase failing bank assets. In 2009, the Obama administration pushed through the American Recovery and Reinvestment Act, an $800 billion stimulus package that included tax cuts, infrastructure spending, and aid to state and local governments.
The economy slowly recovered, with unemployment gradually decreasing and the stock market eventually reaching new heights. However, the recovery was uneven, with many Americans continuing to struggle financially and wealth inequality increasing.
Environmental issues became increasingly urgent in the 21st century, particularly concerns about climate change and America's dependence on fossil fuels.
Scientific consensus strengthened that human activities, especially burning fossil fuels, were causing global warming with potentially severe consequences. At the same time, U.S. involvement in Middle East conflicts highlighted the strategic vulnerability created by dependence on foreign oil.
Environmental policy became increasingly polarized, with significant differences between Democratic and Republican administrations. While the Obama administration emphasized climate action and clean energy development, the Trump administration rolled back many environmental regulations and withdrew from international climate agreements.
The early 21st century saw the rise of significant social movements and increasing political polarization in American society.
After the 2008 financial crisis, the Occupy Wall Street movement emerged to protest economic inequality and corporate influence in politics. The Tea Party movement arose as a conservative response to government spending and the Obama administration's policies. Later, police killings of unarmed Black Americans sparked the Black Lives Matter movement.
Political tribalism intensified, with Americans increasingly seeing those from the opposing party as not just wrong on issues but fundamentally different in values and threatening to the country's future. This polarization made addressing national challenges more difficult as compromise became harder to achieve.
Despite the challenges of the 21st century, the United States maintained its position as the world's leading superpower, though its global leadership faced new tests.
The rise of China as an economic powerhouse, Russia's renewed aggression under Vladimir Putin, and persistent challenges from regional powers and non-state actors created a more complex international environment. The United States continued to lead economically and militarily but faced questions about its leadership role in a changing world.
Through these challenges, the United States remained the world's most powerful nation militarily and economically, but questions about American leadership, values, and the future of global cooperation intensified. The future of American power depends on how the nation addresses both domestic divisions and international challenges in the years ahead.
The early 21st century has tested America's resilience through terrorism, war, economic crisis, and environmental threats. Despite these challenges, the United States has maintained its position as a global superpower while wrestling with difficult questions about security, liberty, economic equality, and environmental responsibility. How America balances these competing priorities will determine its future strength and influence in the world.