We have ONE (1) senate seat.
The Liberals are in the same situation.
This seems like a good time to pull out my crudely-assembled chart:
Looking at this chart I see seven Senators who are undeniably on the left of the political spectrum. To claim that the five TPP Senators are somehow centrists or rightists is absurd if you look at their voting and legislative record and their political philosophy. The mere fact they aren't part of the Liberal Party or the Labor Party doesn't make these guys conservative ...
I think of my self as being part of the Atlasian center-left, but part of that is because its within the context of Atlasian politics. That said, my governing style is rooted in principled pragmatism and a belief that real compromises often produce better results than hyper-partisanship and/or strict ideological rigidity. But I'd still never call myself an ideological centrist and in the context of American politics I'm definitely a liberal. I think that when considering the left-right ideological spectrum, it is equally important to take into account an individual's governing style. If two people have identical issue positions, but one is far more rigid and generally unwilling to compromise, he/she will often be perceived as more extreme than the other person even if ideology alone wouldn't suggest that this was the case.