The European Union finds itself badly and uncomfortably divided into three camps on the question of nonmember U.N. observer status for Palestine: those opposed, those supporting, and those ambivalent about such an upgrade. The Europeans have been negotiating among themselves to try to find a formula they could unite behind and also provide some diplomatic benefits acceptable to the Palestinians.
European countries worried about Palestinian access to the ICC blocked a Spanish-French proposal for nonmember observer status for Palestine, and there has even been discussion among Europeans about creating a new legal status for the Palestinians that would provide an upgrade in status but block potential access to the ICC and other international legal enforcement agencies.
Even if the Palestinians got nonmember state status at the U.N., which is the maximum they could achieve under the present circumstances, and were able to become party to the ICC, there are serious doubts about their practical ability to bring charges against Israel or Israeli officials. Any request for such charges would be more a diplomatic and political question than a legal one, and both the ICC and prosecutors would be subject to significant domestic and international political pressures that make it hard to imagine such a scenario actually unfolding.
The recent history of the ICC suggests that diplomatic and political realities are more important than ICC membership in prompting such indictments. The Goldstone Report on the Gaza War, for example, accused both Israel and Hamas of serious war crimes, but this was not acted on by the ICC. Opposition came not only from traditional defenders of Israel like the United States and France, but also from Russia and China, who were worried about the potential precedent regarding the behavior of military forces acting against guerrillas or insurgents in heavily populated areas.
By contrast, neither Sudan nor Libya were parties to the ICC, and the areas in which their militaries were operating were, at the time, within the sovereign territory of their governments. This did not prevent the U.N. Security Council from authorizing investigations that led to the indictments of Sudanese President Omar Bashir and Libyan leader Moammar Qaddafi and some of his sons.
Both of these examples strongly suggest that the international diplomatic and political climate is much more important to securing ICC indictments than membership in that organization. And the indictment of Bashir has not been acted on. He even attended the independence ceremony of the new Republic of South Sudan, standing in the presence of U.N. Secretary General Ban and many other world leaders. These precedents suggest that whatever technical advantages the Palestinians might gain from a U.N. upgrade, they will still face significant hurdles to legal action. Under the present international political and diplomatic climate, it's quite difficult to imagine any international law enforcement agency such as the ICC actually bringing charges against Israel.