There is no doubt that the arrival of the International Criminal Court (ICC) has had a significant effect on international justice and security. What that impact is and whether it is positive or negative are still open academic questions, with some scholars saying the ICC deters atrocities and prevents a culture of impunity, while others say it causes worse human suffering since violence endures. One area of impact is in peace negotiations to end civil wars, and there has been much speculation that the judicial requirements of the ICC tie the hands of the parties. Are amnesties still an option? To date, we lack a theory of how the ICC affects the process of trying to reach a peace settlement. Where previously there were two actors, now there are three actors, all with different preferences. This article develops a model of the interaction between government, rebels and ICC. This model is then examined with respect to Colombia, where negotiations between the government and the Revolutionary Armed Forces of Colombia (FARC) have taken place in the shadow of the ICC, to examine how much room for manoeuvre the government has. The article argues that the ICC impacts on the negotiations not only by removing one of the incentives that a government can offer rebels, but moreover by ignoring the political trade-offs required. By doing so, the ICC risks jeopardizing a settlement that offers substantial transitional justice. However, I also find that the government has substantial room for manoeuvre. Furthermore, the article argues, somewhat counterintuitively, that not taking a hard-line stance allows the ICC to maximize justice.