Why? It's a battle has no chance of winning. Why spend political capital on it? It's not like Obama has been eagar to please the liberal base before, why try to do so on this issue? Americans like guns, get over it.
Suburban swing voters swung nasty in 2010. And there you have it, perhaps.
Well maybe, although I believe American suburban swing voters could care less about gun legislation as their neighberhoods isn't the ones with the gun problems. There might be some popularity right now due to the recent shootings, but I believe it will seem really irrelevant in a few months to those voters, and they might just be annoyed that once again Obama allows himself to be distracted from creating jobs and get the economy going. I asume he could also do it because he belives it's right, but even so he must realise he'll never get it through the house and the filibuster, and that losinging on something like that would only make him seem weak.
Suburbanites tend to believe that their livelihoods are under threat from guns (drugs too, but those are already illegal), even though such views are essentially unfounded. Hence they support restricting these things, even though they have little to no understanding of the actual issues. The sweet thing is that this generally begets laughably ineffectual gun control measures, such as the AWB.