Amid the escalation of violence in Gaza, tensions between Lebanese Hezbollah and Israel are steadily increasing. However, while the Israel-Lebanon border has seen sporadic clashes, an all-out confrontation has yet to unfold. Instead, what has stood out in recent days is the signaling by Iraqi Shiite armed groups that they are also ready to confront Israel. For instance, in the aftermath of the Hamas movement’s Oct. 7 surprise attack on Israel, the commander of a powerful Iran-backed Iraqi faction has made an appearance in southern Lebanon.

In this context, Iran’s warning that Israel’s attack on Gaza may trigger the “opening of new fronts” raises questions about where a confrontation between Iraqi groups and Israel may take place—and under what conditions. Importantly, there is also the prospect that American rather than Israeli targets may become...