Twenty-five years after the September 11, 2001 attacks, the United States has undergone significant transformations in its foreign policy framework and international relationships, according to analysis by former U.S. Representative Jane Harman. While Americans continue to honor the memory of those lost with annual ceremonies, the lasting impact of 9/11 on the country’s governance and global standing has fundamentally reshaped how it engages with the world.

The 9/11 attacks were a pivotal moment that led to a generation of U.S. foreign policy initiatives centered on counterterrorism. The successful mission that resulted in the killing of Osama bin Laden marked a major achievement, and the U.S. has avoided another comparable large-scale attack since. However, the government’s structure and diplomatic approach have shifted dramatically. Congress has ceded considerable authority to the executive branch, while diplomatic institutions have experienced significant reductions in resources and influence. Meanwhile, defense spending has soared to unprecedented levels, reaching around $40 trillion since 2001, the highest share of the economy dedicated to defense since World War II.

The immediate legislative response to 9/11 was swift: three days after the attacks, Congress passed the Authorization for Use of Military Force (AUMF) with only one dissenting vote. This authorization granted the president broad powers to target those responsible or affiliated with the attacks. Although the primary objectives—such as eliminating bin Laden and capturing others—were largely achieved, the 2001 AUMF remains active and has been repeatedly used by successive administrations to justify various military operations, including warrantless surveillance, indefinite detention, and drone strikes beyond the initial theaters of Afghanistan and Iraq. No significant attempt to repeal or amend the AUMF has succeeded, reflecting a lack of congressional oversight and bipartisan consensus.

The balance between military force and diplomacy has also shifted notably. The State Department and diplomatic efforts have been undermined amid growing defense expenditures. This transformation coincided with fraying relations with longstanding allies. Following 9/11, NATO invoked Article 5—its mutual defense clause—for the first time ever, rallying European and Canadian support in military operations alongside the U.S. However, disagreements soon emerged, particularly over the Iraq War and concerns about the burden-sharing of Europe’s own defense responsibilities. Efforts by NATO members to enhance their defense funding were met with retaliatory tariffs and contentious demands from the U.S., including a rejected proposition by the Trump administration to buy Greenland. Additionally, the U.S. response to conflicts such as those involving Ukraine and Iran has, at times, taken place with limited consultation or support from allies.

Today’s younger American generation has not experienced Congress explicitly authorizing war or witnessed a fully funded diplomatic corps. Instead, they see a government heavily reliant on military solutions, significant national debt, and an erosion of trust among international partners. This shift has led many to view the current state of U.S. foreign policy as the norm, even though it represents a departure from the more balanced and multilateral approach that characterized the pre-9/11 era. The long-term consequence, Harman argues, is not just a changed country but one that has lost sight of the possibility of functioning differently on the global stage.