The Trump administration is reshaping U.S. defense doctrine away from nation-building interventions toward what Pentagon officials call "denial-based deterrence," focusing on limiting adversaries rather than overthrowing governments.
Under Secretary of Defense for Policy Elbridge Colby announced a Pentagon review of America's nuclear posture this week, focused on providing more "options" for the White House. The review centers on shorter-range tactical nuclear weapons for potential use in regional conflicts, with the goal of maintaining deterrence and stability.
Colby emphasized the term "options" while stressing he had "no announcement of any kind of change" regarding current nuclear policy, noting the review examined "employment guidance" between strategic command and the Defense Secretary. He said the review would not be released to the general public.
The nuclear strategy shift accompanies a broader Pentagon pivot. The 2026 National Defense Strategy emphasizes burden-sharing with allies and defense of the U.S. homeland and deterrence of China as priorities, moving away from global military presence. The strategy emphasizes "denial-based deterrence"—preventing China from rapidly achieving its objectives in the Indo-Pacific—rather than asserting global primacy.
On regime change specifically, War Secretary Pete Hegseth drew a distinction between the Iran operation and past interventions. Hegseth stated the U.S.-Iran campaign was "not a so-called regime change war" and declared "This is not Iraq, this is not endless." He added: "This is the opposite" of nation-building wars, calling previous strategies "dumb."
However, Hegseth's position conflicted with earlier Trump rhetoric. While Hegseth said the war was not about regime change, Trump had openly endorsed it, telling Iranians "this is your moment" to take over their government.
