This is based on a comment I made here.
The US has a legislated two Party system. (Left-cynics say that if the Soviet Communist Party had divided itself into two wings who disagreed on abortion, it would still be in power.)
The UK has working class voters who will never vote Tory, so the Labour Party can take them for granted (but we will see how well the Brexit Party does in such seats on Dec.12).
Political economist Thomas Piketty has pointed out (pdf) that politics has become dominated by a struggle between an educated (human capital) elite on the centre-left and a business (commercial capital) elite on the centre-right. Which often leaves working class voters trying to work out which side of politics will betray them least.
In Australia, compulsory voting and preferential voting means you cannot drive groups away from voting, but must aim for 50%+1. So working class voters can’t be ignored.
In Canada, class voting is a lot weaker than in the UK, and the Conservative/Liberal/NDP/Quebecois struggle also means that significant slabs of voters cannot be left out.
Australia and Canada have high migration policies whose content minimises any costs, and maximises any benefit, to local working class voters. Migration is a peripheral issue in politics, provided there is border control.
Remembering that the benefits of migration go first overwhelmingly to migrants and then to the holders of capital with local providers of labour being, at most, marginal beneficiaries and, if factors not normally included in the current economic literature regarding migration are included (disruption of local networks, pressure on culture and institutions, notably from physical and institutional congestion), are much more likely to be net losers, even over the longer term.
UK and US have much lower levels of migration than Australia or Canada, but there is very little effort made to ensure migration minimise costs, or maximises benefit, to local working class voters. There are much higher levels of alienation and polarisation in US and UK politics compared to Australia and Canadian politics. This presentation, for example, documents the alienation of working class voters in the UK.
The polarising/alienating effect is particularly likely to kick in, given that evidence suggests, the less control voters have over matters of concern for them, the more likely they are to take refuge in some congenial identity.
If democratic politics becomes dominated by the interests of capital (human or commercial) in a way that leaves working class voters largely frozen out, politics becomes increasingly dysfunctional. A process that, in the US, the dominance of donor class and interest group preferences in policy outcomes (pdf) intensifies. Indeed, political rhetoric tends to become more febrile the more intense the gap between donor (and activist) preferences and the voter base becomes, in an attempt to cover that gap. (The Republicans and British Labour being cases in point, though the Democrats seem to be more than catching up.)
Show me a country with high levels of polarisation, and the chances are that working class voters are not having their concerns and interests addressed by mainstream politics.
[Cross-posted from Thinking Out Aloud.]