The UK as one-party state

We live in hope, but the overwhelming probability is still that Theresa May will win next month's election by a landslide that effectively makes it impossible for Labour to win a majority in 2022. If that happens, then from 1979 to 2027 the UK government will have changed partisan hands two and a half times. Forty-eight years with only two changes of government, or three if you insist on taking the Lib Dems seriously.

This is not normal. Even counting only to now, not ten years into the future, Australia has had four changes since 1979; the USA, at least five, probably eight; France, somewhere between three (if you count Presidents, with their very long terms) and seven (if you count Prime Ministers).*

The story only gets stranger if you think about what politics has actually looked like during these long stretches. For most of its recent political history, the UK has resembled a one-party state in which the only opposition sat in total disarray, apparently incapable of mounting any serious challenge to the government even when it has been in power for a decade. What's going on?

I'll keep this short and speculative, because I don't know. (If anyone reading with more political science background has ideas, I'd love to hear them.) But some vague thoughts:

The terms are long
The obvious consequence of longer electoral terms is that there just aren't as many opportunities for power to change hands. (There were eight British general elections between 1979 and 2016, compared to 14 Australian federal votes.) That immediately means governments hold power for longer.

Perhaps more importantly, though, it means opposition parties are liable to panic when they lose an election. Only one UK opposition leader in this spell has contested two elections. The aftermath of the 2015 election illustrates the dynamic: being out of power until 2020 was already close to apocalyptic, and the stakes of the internal party fight struck everyone as extremely high - if the 'wrong' side (whichever one you thought that was) won, that meant a decade in the wilderness. This is the kind of situation that encourages politicians to think they need a dramatic break with what's gone before.  Arguably the 2015 performance was (Scotland aside) more or less what you'd expect, not cause for deep introspection. I wonder occasionally what the political landscape would look like now if Ed Miliband had stayed on as opposition leader, because it seems possible he'd have been a more credible anti-Brexit messenger and certainly much better placed to exploit Tory divisions and Theresa May's wholesale ripping-off of his platform. But with such a long time between votes, this message - that not beating a first-term government is alright and that there was no need to reopen big internal debates - was never going to have many sympathetic ears.

Rabid but changeable media
I don't think there's that much to say about this. The press was very solid for Thatcher and Major, then assiduously courted by New Labour, now firmly pro-Tory again. The aggressive Fleet Street style means that whichever party is getting support gets it in a big way, and the other party gets very vicious treatment. Throw in that the media landscape is mostly characterised by individual owners, with more or less transparent desires to seek influence, and it's not surprising that the attack dogs have mostly tended to line up behind the party currently in power.

Vote distribution
It's actually not clear to me how this point works, but it's something worth highlighting. The changes to constituency boundaries which will come into effect next year were a response to the fact that Labour under Tony Blair had a significantly more efficiently spread vote than the Tories, so could win elections with lower shares of the national vote. In 2015, and much more acutely this year, Labour seems to be racking up votes in an extremely inefficient way - in safe Labour seats, and in Lib Dem-Tory marginals - so that even the recent improvement in its polling position doesn't look likely to insulate it from a parliamentary wipeout. Perhaps it's coincidental that the governing parties in recent years have managed to campaign better and accrue their votes in more strategically helpful places; I don't have any other theory. But it was clearly an important factor in New Labour having such large majorities, and is rapidly becoming an important factor in the dominance of May's Conservatives.

One striking thing, which I don't know how to connect to this phenomenon, is that the UK is unusual among mature democracies in having almost no significant lower levels of government. There are no doubt others. In general, the way governments manage to get unusually deeply entrenched has to be worth thinking more about.

* Perhaps surprisingly this is a bit of art, not pure science. My counts:
Australia: Hawke (1983); Howard (1996); Rudd (2007); Abbott (2013).
France: Mitterrand (1981); Chirac (PM, 1986); Mitterrand (1988); Balladur (PM, 1993); Jospin (PM, 1997; Chirac (2002); Hollande (2012).
USA: Reagan (1980); Clinton (1992); Gingrich (1994); Bush (2000); Pelosi (2006); Obama (2008); Boehner (2010); Trump (2016). I've included three Congressional flips, fairly arbitrarily, because they seem like particularly significant ones.