On Thursday, John Kerry claimed that if one "puts the dots together" from reading the UN's official report on Syria, it becomes abundantly clear that President Bashar al-Assad orchestrated the attack on his own people.
When the White House initially announced its intent to launch punitive missile strikes against the country, major powers like Russia, China, and the UK got skittish and refused to participate. Hang on, they begged, and wait until the UN finds evidence — then we'll collaborate and figure out a response together. America wasn't having any of it, and was all set to launch strikes, pending Congressional approval, when Syria unexpectedly accepted a treaty courtesy of Russia — which involved them cordoning off all their chemical weapons and allowing them to be destroyed.
With no strikes and no punishment, if Kerry is right and Assad is responsible for the death of over a thousand people via chemical weapons, we have another diplomatic issue pending. Namely: what is the world going to do about it? Assad is handing over the country's weapons, meaning that there theoretically won't be a repeat incident, but by international standards (or that famous phrase, "international norms,") mass homicide deserves punishment.
The international community has pointed fingers at the International Criminal Court, overseen but not controlled by the UN, which was set up specifically in 2002 to deal with war crimes, genocide, and crimes against humanity. But it has only 122 members, doesn't include most of the Middle East, and 31 more countries haven't officially ratified their agreement to join — including Russia, the United States, and Syria. This poses a problem, because to be un-ratified means that they're not technically official members.
If the UN Security Council were to refer Assad to the ICC, then he would be tried by the court. But this probably won't happen: he now needs to be in Syria to carry out the chemical-weapons agreement, as promised, and America wants to keep him there to prevent extremists from overthrowing Syria. He's protected by Russia, and the ICC isn't particularly keen on trying him anyway, because they already have a dangerous reputation of only prosecuting poor and underdeveloped countries.
The ICC is a relatively new tribunal, but is already weighed down by the same issues that faced the doomed League Of Nations more than a half-century ago. Because neither group had their own military, nor an independent right to dictate punishment, their power was and is severely diminished — and the less power they have, the less effective they are, and less powers are likely to do what they say. (The League of Nations was dismissed after the Second World War, when it was clear that they had not actually managed to prevent a world war.)
In short, an international tribunal is only as powerful as the countries that agree to sponsor and enforce it — and the League of Nations couldn't do that. The UN, which inherited most of the League's responsibilities, can't either, which is precisely why they created the ICC — but in ten years, the court only successfully convicted one person (a warlord in Congo.)
Some critics are predicting that the ICC's failure to convict Assad will be the nail in the coffin for the agency. After all, if Assad did deliberately plan and carry out an attack against his own people, and the only international tribunal with the power to bring him to justice can't and/or won't — what's the point in it existing?