In countries that enclose disgruntled minorities linked to hostile powers through culture or location, defense planners face a Trojan horse dilemma. Can recruits from these groups be counted on to defend the state? This article is the first to examine the manpower policies chosen in response to this dilemma in Estonia, a small republic that inherited a large Russian population of Soviet-era settlers in 1991. It builds on historical records and recent opinion polls, which give cause for concern for Estonian defense planners contemplating the allegiance of Russian heritage soldiers. But elite interviews (N = 29) suggest that force professionalism and republican rhetoric obstruct fifth column fears from influencing manpower policies. Officers created institutions that permit recruits to prove themselves on merit while the republican citizenship discourse deterred politicians from singling out “ethnic soldiers”—thus facilitating integration.