The answer is that things could nearly always be worse. In this specific instance, what prompts the question is something that Matt Singh, of Number Cruncher Politics, noticed in the cross-breaks for our latest Welsh Political Barometer poll. Put simply, the point is that, at least for Westminster voting intention, Labour is doing particularly well among those respondents who apparently did not vote in the June EU referendum – and rather badly among many of those who did vote. If we take out non-voters in the referendum, Labour has pretty much no lead at all on general election voting intention.
I went back and checked the September Barometer poll, and something of the same pattern appears, although to a less strong extent. Plaid Cymru, we should notice, also do relatively well among those who did not vote in the referendum. And as Matt speculates, “While 2016 taught us to be cautious when it comes to making assumptions about turnout, it’s nevertheless still reasonable to think that people that didn’t vote in a referendum with a 72 per cent turnout probably aren’t the likeliest of voters in a general election. The risk for Labour is that their lead is soft because they’re relying in part on this type of (non-) voter and the Tories aren’t.”
You can find Matt’s discussion here. It’s worth a read.