How does partisan identification shape the attitudes of US military officers toward the protection of civilians in war? Drawing on unique cross-cohort surveys of soon-to-be commissioned officers in 12 Army Reserve Officers’ Training Corps (ROTC) training battalions, we find that Democratic-leaning cadets generally prioritize norms of civilian protection more than Republican-leaning cadets when confronted with competing values of military advantage and force protection as part of a ‘combatant’s trilemma’. This gap remains partially resilient after sustained exposure to military training and socialization, including in the norms of restraint embodied by principles of combat ethics and the law of war. We attribute these partisan differences to insights from Moral Foundations Theory (MFT), which suggests that the moral values of Democrats and Republicans guide their views toward the individual use of force in combat. Our findings have important implications for comprehending the impact of political ideology and military training and socialization on attitudes regarding restraint toward civilians in war. Given the widely recognized conservative composition of the US military’s membership, these findings may help to further inform understanding of US military operations and the underlying causes of US adherence to – or violation of – the laws of armed conflict.

党派认同如何塑造美国军官在战争中保护平民的态度？根据对 12 个陆军预备役军官训练团 (ROTC) 训练营中即将上任的军官的独特跨队列调查，我们发现，在面对时，倾向于民主党的学员通常比倾向于共和党的学员更优先考虑平民保护规范军事优势和部队保护的相互竞争的价值观是“战斗人员的三难困境”的一部分。在持续接受​​军事训练和社会化（包括战斗伦理原则和战争法所体现的克制规范）后，这一差距仍然具有部分弹性。我们将这些党派差异归因于道德基础理论（MFT）的见解，这表明民主党人和共和党人的道德价值观引导他们对个人在战斗中使用武力的看法。我们的研究结果对于理解政治意识形态、军事训练和社会化对战争中对平民的克制态度的影响具有重要意义。鉴于公认的美国军方成员的保守构成，这些发现可能有助于进一步了解美国的军事行动以及美国遵守或违反武装冲突法的根本原因。