A recent trend in the literature has identified the significance of nonviolent protest movements in international law, in particular with regard to the right of self-determination, democracy, and human rights. Protests, so it is argued, are the only avenue for popular involvement in public affairs when the institutional participation mechanisms are dysfunctional or shut-off. Against this backdrop, a foreign military intervention that supports an embattled government in quashing popular and nonviolent protests raises questions under international law even when exercised at the request of the respective government. Taking into account the January 2022 intervention by the Collective Security Treaty Organization (CSTO) in Kazakhstan we develop an argument to outlaw outside military interventions in support of a government faced with a nonviolent protest movement. First, we outline the events in Kazakhstan and justifications for the intervention (B.). Then, the three possible limitations upon an intervention by invitation are detailed (C.). If a nonviolent protest movement fulfills certain criteria and faces an autocratic government that government could lose its authority to issue invitations (C.I.). Furthermore, an intervention to quash a nonviolent protest movement could violate the population’s right to self-determination (C.II.). Additionally, quashing popular and nonviolent dissent is a purpose incompatible with fundamental principles of International Law (C.III.). Drawing upon the example of the intervention in Kazakhstan, we show how these limitations would apply in practice. To conclude, we set out the argument against military interventions by invitation to quash nonviolent protests and provide an outlook for the further development of this practice (D.).