They aren't. The US doesn't have a serious left wing voice on capital hill, aside from maybe a person here or there. They have right of centre, right, and crazy screaming rabid hyena right. My own politics are what I'd consider left to left of centre. There are lots and lots of people farther left than me and while they may not have a lot of representation in govenment here, there is at least the sense that there is representation even out that far left. For the mainstream left, and centre left there is quite a lot of representation. And I'm not talking about having separate left wing political parties, voting in MPs (senators, members of congress whatever title they may have) is all the representation I mean. Like I said I know there are a few voices here and there in the US that ARE liberal/left in this sense but from a global perspective they are extremely underrepresented. For example we currently have a majority conservative government, and fairly conservative at that (at least from a global point of view) and yet the major opposition party is the NDP (a party with many views to the left of my own).
It always stuns me when people in the US get riled up about the liberal media, the left wing this, the left wing that. There IS no left wing to talk about for the most part. You are kidding yourself if you think Obama is anything but a centrist, and right of centre on a lot of things.
QUESTION FOR THOSE OF YOU HERE LIVING IN THE US WHO SELF IDENTIFY AS LEFT WING: Do you agree with the above assessment or not?