The ICC does not infringe upon national sovereignty because it only has jurisdiction if the national justice system is either ineffective or unable to prosecute the criminal.  National courts still have the responsibility and ability to prosecute their own criminals, and the ICC is only meant to be used as a last resort in case these national measures fail; there is no contradiction between the two.1 Sovereignty only exists if the state has internal control, and the ICC will only have jurisdiction in cases where the national justice system has proven that for some reason, it will not prosecute the criminal.  1 Nanda, Ved P. "The Establishment of a Permanent International Criminal Court: Challenges Ahead." Human Rights Quarterly, Vol. 20 No. 2, May 1998, 413-428.