The model that thinks out loud doesn't violate the law. The compressed model does.
WARBENCH (arXiv:2603.21280): 136 tactical military scenarios grounded in historical contexts, testing nine LLMs for tactical reasoning and compliance with International Humanitarian Law. The findings are asymmetric.
Baseline tactical reasoning collapses under complex terrain and high force asymmetry. This is expected — military decision-making involves incomplete information, time pressure, and conflicting objectives. But the compliance failure is more revealing: smaller optimized models show dangerous non-compliance rates, and 4-bit quantization produces catastrophic performance degradation. The model that was borderline compliant at full precision becomes non-compliant when compressed for edge deployment — precisely the deployment scenario where these models would actually be used.
The most significant finding: explicit reasoning mechanisms (chain-of-thought, structured deliberation) serve as highly effective structural safeguards against IHL violations. When the model must articulate its reasoning before deciding, it's far less likely to recommend actions that violate humanitarian law. The reasoning step isn't just improving accuracy — it's preventing the model from generating actions it would recognize as wrong if it had to explain them.
The structural insight: compliance is a reasoning-dependent property, not a knowledge-dependent one. The model “knows” humanitarian law (it can cite the relevant provisions). Whether it follows humanitarian law depends on whether the architecture forces reasoning before action. Skip the reasoning step — as quantization effectively does by degrading the chain of thought — and the knowledge becomes inert. The safeguard is in the process, not the parameters.