When two tribes go into coalition.
There's something about the SNP and the Liberals in coalition at local authority level which really doesn't work, as we've been finding out since May 2007.
A chunk of the electorate vote for the SNP milk, and others back the Liberal orange juice, but then the results come in and it all gets poured into the same glass. Unpleasant.
The best explanation I have for this is to do with political principles. The SNP have a single such principle, but sadly it doesn't tell you anything about how to run a local authority beyond "don't embarrass the First Minister otherwise people won't ever vote for independence".
On the other side, it's hard to identify whether any Liberal principles survive into the modern age. They're for Heathrow expansion and against it, they're for SUV-specific congestion charges and against them, for incinerators and against them, and the list goes on.
The useful thing about having more principles is that it helps you make consistent decisions, decisions which your electorate could rightfully expect you to make. Otherwise you tend to follow what the local paper says as a substitute for leadership or even accountability, or just to twist in the wind of your internal politics.
Edinburgh is a great example. Local residents can only watch as an incompetent administration makes a fist of a public transport scheme that only one of the parties wanted. The SNP in particular constantly bitch about the chaos caused by the installation of the first tram line, while somehow not noticing that they've been in charge of it for more than two years now. Having failed to block it altogether, it's like they've decided to deliver it as incompetently as possible to prove they were right.
The bin dispute is another classic, where a decision devoid of principle has come back to bite them hard. Why don't we offer staff a -50% pay rise and see what happens? Oh, a strike, you say? Jenny Dawe's approach here will be useful to future textbook writers as a case study for how not to treat those already on low pay but properly unionised.
In Aberdeen, it's fair, this same glass of curdled politics inherited a spectacular hole from the last administration, but the Liberals were in that coalition too, so my instinct is to blame them. They did avoid going bankrupt, which is great, and recent reports suggest some progress, but Aberdeen City Council is still hardly a role model for others.
East Lothian Council has largely avoided problems on this scale, but this week's defection of a husband-and-wife pair of Liberal councillors to their SNP coalition partners must be making for some tense times in the Council chambers and probably some awkward family photos. Here's the previous round of (wildly inaccurate) speculation on the subject for reference. Sounds like fun!