I don't get how they figure he was a supporting actor, especially when you compare it to Anthony Hopkins winning Best Lead Actor for Silence of the Lambs when he was in it for less than 20 minutes.
Screen time is but one way to measure the importance of a role. Clearly Bob (Clooney's character) was neither the main person driving the plot forward nor the main person being driven forward by it. Syriana is an ensemble piece and I don't think anyone was the lead (and if you want to give lead role to any character in Syriana, I think it should be Holiday).
- Anwar
--- One man's sockpuppet is another man's freedom fighter.