These 2 statements seem to contradict each other:
"the tricky question of whether a member state is obliged to enforce an arrest warrant on a visiting leader from a country such as Sudan, which is not a member of the court."
"The court cannot prosecute anyone in the United States, Russia, China or other non-member states,"

If the court cannot prosecute someone from a non-member state, how can it issue an arrest warrant for someone from non-member Sudan?