Happy Birthday ACI! 109 Years Young Today!

Happy 109th Birthday, U.S. Army Counterintelligence (ACI)!

On 13 August 1917, the U.S. Army established what would become its permanent counterintelligence service. At the request of American Expeditionary Forces G-2 Major Dennis Nolan, the Army began assembling a small group of men with investigative and police experience to support counterespionage operations in Europe. That organization became the Corps of Intelligence Police (CIP)—and the beginning of the Army Counterintelligence lineage we continue today.

Those first agents entered a world of German espionage, sabotage, subversion, and wartime intrigue. They operated at ports and along the front, investigated suspected enemy agents, conducted undercover operations, protected sensitive military activities, and provided security for senior leaders, including General John J. Pershing. Much of their work was deliberately conducted in the shadows, meaning many of their accomplishments would never be widely known.

But the organization they created endured.

From the Corps of Intelligence Police of World War I, to the massive expansion and redesignation as the Counter Intelligence Corps (CIC) during World War II, through the Cold War, Korea, Vietnam, the Global War on Terrorism, and the challenges of great-power competition today, generations of Army CI Special Agents have carried forward the same fundamental mission: identify, investigate, exploit, and defeat threats to the United States Army and our national security.

ACI's history extends even further into America's past. We can look to John Jay and the intelligence networks of the Revolutionary War, the Culper Ring, and Allan Pinkerton's detectives hunting Confederate spies during the Civil War as predecessors in the American counterintelligence tradition. But 13 August 1917 represents something different: the establishment of the permanent Army organization from which today's ACI directly evolved.

That continuous unbroken lineage—from CIP, to CIC, to ACI, and ultimately to today's Army Counterintelligence Command (ACIC)—is why we proudly recognize 13 August as the birthday of U.S. Army Counterintelligence. For 109 years, Special Agents of ACI have worked in places both famous and forgotten, during war and peace, overtly and undercover, often without recognition and sometimes without anyone outside the profession ever knowing what they accomplished.

That is the nature of the mission.

Today, the Army Counterintelligence Special Agents Association (ACISAA) honors those first CIP agents and every generation of Special Agents who followed them.

Happy 109th Birthday, ACI.

109 years in the shadows. 109 years protecting the force. 109 years defending the Nation.

Keep up the good fight.