The impact of US allocation of family planning aid on other donors is studied in order to gain new insights into donor interactions. Within this context, the dominant player in the sector is the United States, whose policies on family planning undergo changes influenced by domestic debates surrounding abortion. By utilizing the Mexico City Policy and considering exposure to this particular policy as an instrumental factor, it has been observed that other donors do not immediately react to policy changes made by the United States, either contemporaneously or within one year. However, a noticeable shift occurs after a two-year period, indicating that these donors eventually align their allocation strategies with those of the United States. Further analysis of this phenomenon reveals varying patterns among different types of donors. While smaller donors exhibit a clear intention to compensate for US policy changes, larger donors display a mix of competitive tendencies and herding behavior, thereby reinforcing the impact of the Mexico City Policy after the two-year time frame.