In explaining why he's against abortion Mehdi Hasan wrote that being so didn't make him 'any less of a lefty'. Some have duly responded to him in the terms in which he chose to frame the question, saying that he cannot be left-wing if he takes the view he does.
Though I don't agree with Hasan on the substantive issue, it's not why I'm posting this. I'm posting to ask the following question: who gives a cup of cold weak tea whether or not on some particular moral issue the view a person adopts is (regarded as being) left-wing? OK, some people do give a lot more than that, but they shouldn't. Here's why.
Simplifying, we can delineate four possibilities: a viewpoint may be (a) left-wing and morally sound, (b) left-wing and morally unsound, (c) not left-wing and morally sound, or (d) not left-wing and morally unsound. The interesting options here are (b) and (c). We can dispose of (a) because if the view is left-wing and morally sound, someone on the left need have no worries; and we can dispose of (d) because if the view is morally unsound, you shouldn't be adopting it wherever it is thought to lie on the political spectrum. But as between (b) and (c), there's a choice to be made and (c) is the better choice: morally sound even though not left-wing is better than morally unsound, whatever.
In response to this it might be said that the left-wing/not-left-wing way of posing the question is a kind of shorthand. We on the left assume left-wing positions to be better than non-left-wing positions, and so if a viewpoint isn't left-wing that's likely to be bad for it. But this won't work. Even those on the left who do make an assumption of the kind I've just characterized (which they shouldn't) must believe that 'left is good' comes out of the moral viewpoints of the left being better than other moral viewpoints. That's the way the 'arrow of influence' goes; it can't just be that anything called or thought of as 'left' is going to be good. It can't because - observe - if you call mass murder left-wing, or think of it as left-wing, this won't make it good. Therefore, you have to figure out whether a particular position is morally justifiable even if it's (considered) left-wing, since left-wing only gets to be good for you via the moral positions that compose it; it's not the other way round.
This must be the case for anyone unless they believe that the mere fact of most left-wing people's thinking something to be good or right makes it so. Not only is that a belief too preposterous for any rational person to entertain, we already know historically that it has been false, since large numbers of yesterday's leftists supported actions and practices which today's leftists no longer feel able to defend; and, for that matter, some of today's leftists still support actions and practices that are morally indefensible.
It doesn't matter whether your view about something is left-wing or not independently of what can be argued in justification of that view.