Spain and International Law

Well Spain is doing it again, trying to make their court system to enforce international law. Spain in the past has charged former dictators from other countries, Pinochet is an example. Pinochet was never put on trial for the crimes that were done during his time in power, the British decided that he was too old and sick to be put on trial. This time the Spanish government is putting some of the current Rwandan government officials on trial, over their actions after the genocide had occurred.
I find it interesting that they will charge the people who stopped the genocide and not as well charge the people who did the genocide. It appears like they only care when the actions go against their citizens. Also the Spanish were not even in Rwanda during the civil war and genocide, this begs the question could people in Rwanda sue the Spanish government over their lack of action in Rwanda. Or even better a western country charge them with crimes, just like what they are doing now.
This whole issue could be diluted if there was an international court of justice. Which would be able to look at these conflicts without one government charging another one. It would hopefully try to take the politics out of the situation. This court of course was undermined by the Lovely government of George 'W' Bush. One of the many good legacies of that administration.