There's a theme running here I think... It's not a concious effort to draw political caricatures but, like Gaddafi, Obama has also been in the news alot (not that I sit around watching the news all day).
The first drawing was just a pencil sketch, smudged in roughly blending kind of way. After that I thought I'd try a coloured version. I stretched his face a bit on the colour version because on the news he looked as though he had a wider face...maybe it's just the wide screen TV, the American President looks a bit thinner in the paper. (Maybe it's the stress of the job!)