Lachlan MacKenzie

Associate Fellow, Project on Nuclear Issues
Lachlan MacKenzie

Lachlan MacKenzie is an associate fellow with the Project on Nuclear Issues in the Defense and Security Department at the Center for Strategic and International Studies (CSIS). His research focuses on Russian nuclear signaling, two-peer competition, and nuclear modernization. Previously, he interned with the Institute for the Study of War and the Institute for National Strategic Studies. He earned a BA in international relations from Brown University, where he graduated with honors. His thesis explored Russia's motivations for developing novel nuclear delivery systems.

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Audio Briefs

Golden Dome for America: Assessing Chinese and Russian Reactions

An audio version of “⁠Golden Dome for America: Assessing Chinese and Russian Reactions⁠,” a new commentary by CSIS’s Lachlan Mackenzie with Raymond Wang. This audio was generated with text-to-speech by Eleven Labs.

Podcast Episode by Raymond Wang and Lachlan MacKenzie — November 20, 2025

Audio Briefs

Strategic Trends 2025

In a world where old nuclear guardrails are eroding and new rivalries are converging, Strategic Trends 2025 charts how the United States and its allies must navigate a disorderly, multi-adversary nuclear landscape and rethink deterrence for an unpredictable era.

Report by Nicholas Adamopoulos, Diya Ashtakala, Doreen Horschig, Lachlan MacKenzie, Catherine Murphy, Joseph Rodgers, Bailey Schiff, Pranay Vaddi, Heather Williams, and Reja Younis — November 18, 2025

Russia’s Latest Nuclear Saber-Rattling: Nuclear Testing?

President Putin’s instruction for Russian military and political leaders to begin “preparations for nuclear weapons tests” follows President Trump’s similar order last week, but also fits a wider pattern of nuclear saber-rattling tied to the ongoing war in Ukraine.

Critical Questions by Heather Williams and Lachlan MacKenzie — November 5, 2025

Audio Briefs

Ukraine’s Drone Swarms Are Destroying Russian Nuclear Bombers. What Happens Now?

An audio version of “⁠Ukraine’s Drone Swarms Are Destroying Russian Nuclear Bombers. What Happens Now?⁠,” a new Critical Questions by CSIS's Masao Dahlgren and Lachlan MacKenzie. This audio was generated with text-to-speech by Eleven Labs. 

Podcast Episode by Masao Dahlgren and Lachlan MacKenzie — June 4, 2025

Audio Briefs

Game On: Opportunities for Euro-Atlantic Strategic Stability and Arms Control

Europe is likely to remain a theater of instability despite pressure for a peace settlement in Ukraine. As the United States shifts toward the Indo-Pacific and Russia continues to pursue its territorial ambitions, what might arms control look like after the war in Ukraine?

Report by Heather Williams, Nicholas Adamopoulos, Lachlan MacKenzie, and Catherine Murphy — April 21, 2025

Audio Briefs

Why Does the United States Need a More Flexible Nuclear Force?

An audio version of “Why Does the United States Need a More Flexible Nuclear Force?,” a new Critical Questions by CSIS's Heather Williams and Lachlan MacKenzie. This audio was generated with text-to-speech by Eleven Labs.

Podcast Episode by Heather Williams and Lachlan MacKenzie — April 3, 2025

Audio Briefs

Why Does the United States Need a More Flexible Nuclear Force?

Deterrence is emerging as a theme for Secretary of Defense Pete Hegseth, but questions remain about the Trump administration’s ability to deliver and maintain the nation’s nuclear deterrent.

Critical Questions by Heather Williams and Lachlan MacKenzie — April 3, 2025