For U.S. intelligence agencies, the twenty-first century began with a shock, when 19 al Qaeda operatives hijacked four planes and perpetrated the deadliest attack ever on U.S. soil. In the wake of the attack, the intelligence community mobilized with one overriding goal: preventing another 9/11. The CIA, the National Security Agency, and the 15 other components of the U.S. intelligence community restructured, reformed, and retooled. Congress appropriated billions of dollars to support the transformation.

That effort paid off. In the nearly two decades that U.S. intelligence agencies have been focused on fighting terrorists, they have foiled numerous plots to attack the U.S. homeland, tracked down Osama bin Laden, helped eliminate the Islamic State’s caliphate, and found terrorists hiding everywhere from Afghan caves to Brussels apartment complexes. This has arguably been one of the most successful periods in the history of American intelligence.

But today, confronted with new threats that go well beyond terrorism, U.S. intelligence agencies face another moment of reckoning. From biotechnology and nanotechnology to quantum computing and artificial intelligence (AI), rapid technological change is giving U.S. adversaries new capabilities and eroding traditional U.S. intelligence advantages. The U.S. intelligence community must adapt to these shifts or risk failure as the nation’s first line of defense.