International humanitarian law (IHL) prohibits deliberate attacks on civilian objects under both treaty law and customary international law. Article 52 of Additional Protocol I to the Geneva Conventions (1977) prohibits attacking civilian objects and defines military objectives narrowly. The prohibition on attacking civilian infrastructure is also binding as customary international law on all states, including those that have not ratified Additional Protocol I (such as the United States). The ICRC's Customary IHL study, adopted by 161 countries, confirms the prohibition is universal. Power plants, water treatment systems, and hospitals are specifically identified as protected objects under IHL because attacking them causes disproportionate civilian harm. Intentional attacks on civilian infrastructure can constitute war crimes under the Rome Statute of the International Criminal Court.