Can the US block ICC investigations into alleged war crimes by US citizens?
Executive summary
The United States cannot, by domestic law alone, categorically nullify the International Criminal Court’s authority to investigate alleged war crimes by U.S. citizens when those crimes fall within the Court’s jurisdiction, but Washington can—and has—used a suite of political, legal and economic measures to block, deter, or hobble ICC probes in practice [1] [2] [3]. Those measures include non‑cooperation, visa bans, sanctions and seeking Security Council or treaty‑level exemptions, all of which constrain the Court’s effectiveness even where its legal reach exists [4] [5] [6].
1. How ICC jurisdiction over U.S. citizens can arise — and where it stops
The ICC’s legal authority is not universal: it generally can prosecute crimes (war crimes, crimes against humanity, genocide) committed on the territory of States Parties or by nationals of States Parties, or in situations referred by the U.N. Security Council, so alleged misconduct by U.S. personnel abroad can fall within ICC reach if it occurs in a member country such as Afghanistan or if the Security Council refers a situation to the Court [2] [7] [1]. Because the United States never ratified the Rome Statute, crimes committed solely on U.S. soil are generally beyond ICC jurisdiction, and the Court is supposed to defer to genuine national proceedings under the complementarity principle [8] [1].
2. Legal shields and the “complementarity” escape hatch
Article 18‑style mechanisms and the complementarity principle give non‑party states a way to assert primary jurisdiction: if the U.S. can show it is unwilling or unable to investigate and prosecute genuinely, the ICC may step in—but where the U.S. carries out credible domestic prosecutions or builds statutory frameworks to address Rome‑Statute crimes, it reduces the Court’s legal justification to proceed [9] [1]. That is a legal pathway to resist ICC involvement, but it depends on the substance and sincerity of U.S. investigations—an area contested by human rights groups and legal scholars [9] [10].
3. Political instruments Washington has used to block or deter ICC work
When legal arguments are insufficient, the United States has relied on hard power: visa bans on ICC staff announced in 2019; threats and imposition of sanctions and executive orders in 2025 authorizing blocking of ICC property and officials; Congressional proposals to penalize cooperation with the ICC; and diplomatic pressure at the U.N.—all measures designed to punish or deter ICC inquiry into U.S. or allied personnel [1] [11] [4] [6]. These do not erase ICC legal claims but materially impair investigations by restricting cooperation, funding, travel and the Court’s access to evidence and witnesses [3] [12].
4. Enforcement limits: arrests, evidence and the Security Council bottleneck
Even if the ICC issues warrants, it lacks its own police force and depends on States Parties to arrest and surrender suspects, meaning U.S. non‑cooperation or protection of personnel can prevent prosecutions from proceeding in practice [2] [7]. The United States has also used its U.N. Security Council influence historically to secure narrow exemptions for certain forces and to shape investigations, underscoring that geopolitics—not just law—plays a decisive role [5].
5. Competing narratives and the geopolitical stakes
Human rights groups warn that sanctions and bans undermine accountability and the Court’s independence, arguing these measures thwart victims’ access to justice and deter cooperation from NGOs and experts; U.S. officials and some lawmakers counter that exposing American service members and officials to an international tribunal absent consent threatens sovereignty and national security [3] [12] [6]. A mutually acknowledged path out—ratification of the Rome Statute coupled with domestic reforms to meet complementarity standards—remains advocated by some legal scholars as a way to reclaim control while supporting international justice, but political will for that course in Washington has been inconsistent [9].
Conclusion: the United States can substantially block, delay, and deter ICC investigations through political, economic, diplomatic and legal means, and it can make enforcement practically impossible in many instances; it cannot, however, unilaterally and legally erase the Court’s jurisdiction where the Rome Statute authorizes it to act—especially for crimes on member state territory or under a Security Council referral—though the Court’s ability to convert jurisdiction into convictions depends heavily on state cooperation [2] [1] [4].