Reuters reports that the Prosecutor of the International Criminal Court plans to appeal the ruling by Pre-Trial Chamber I of 4 March granting an arrest warrant for crimes against humanity and war crimes, but denying it for the count of genocide: http://www.reuters.com/article/worldNews/idUSTRE52C55S20090313. For the arrest warrant decision, see this blog, 4 March 2009.
There is no general right of appeal or judicial review at the Court, as has already been held in a ruling of the Appeals Chamber (http://www2.icc-cpi.int/NR/exeres/0DEA09C1-52B0-44C3-BA59-ED6289C4405E.htm). Appeals only lie when they are provided for in provisions of the Statute.
There has been one appeal of issuance of an arrest warrant before the Court, but this was taken because it raised an issue of admissibility and was therefore authorised by article 82(1)(a). Otherwise, the Prosecutor must seek leave of the Pre-Trial Chamber, in accordance with article 82(1)(d). The Statute says that leave will only be granted with respect to a decision "that involves an issue that would significantly affect the fair and expeditious conduct of the proceedings or the outcome of the trial, and for which, in the opinion of the Pre-Trial or Trial Chamber, an immediate resolution by the Appeals Chamber may materially advance the proceedings'. Because the charges can always be amended in the course of the proceedings, and because the Trial Chamber may on its own initiative propose the legal requalification of acts that are proven before the Court, and because the evidence of crimes against humanity is arguably the same as that for genocide, it is hard to see how the Prosecutor's appeal could meet the terms of article 82(1)(d).
I am not aware of any precedent for such appeals at the ad hoc tribunals either. At the ad hocs, where counts were denied by the judge issuing the indictment, the Prosecutor just swallowed hard and moved on to other things.
Had the Prosecutor been satisfied with an arrest warrant for crimes against humanity and genocide, it would probably have been granted within a month or two of his application, in July 2008. After all, the Pre-Trial Chamber had already issued warrants on this basis concerning the Situation in Darfur. Why would it take a different approach to Bashir? It is obvious enough that the reason the arrest warrant took so long was the debate about genocide. But any reasonable student of recent legal developments concerning the scope of the crime of genocide could have told the Prosecutor that his chances were slight. He was bucking a trend towards a relatively narrow construction of the definition of genocide that has been confirmed in rulings of the Appeals Chamber of the International Criminal Tribunal for the former Yugoslavia and the International Court of Justice, and in the report of the United Nations Commission of Inquiry into Darfur. Note, in passing, that the major human rights NGOs, Human Rights Watch and Amnesty International, have also prudently resisted using the term ‘genocide’ to describe the situation in Darfur.