As far as Dave need worry, itâ€™s still Europe that matters most
For all the difficulties that have beset Jeremy Corbyn in his first week in charge, when it comes to parliamentary votes, itâ€™s the PM rather than the Leader of the Opposition who should worry. Yes, a more effective whipping operation on the tax credit vote last week would have reduced rather than doubled the government majority but the government would still have won â€“ and a government win is a non-story; majority governments are supposed to win in the Commons. A defeat, on the other hand, defines a media cycle, gives succour to the opposition and can spark a mood of crisis in the government; particularly if several defeats come in short succession.
With a majority of just 10 at the election, the government ought to be vulnerable to even small rebellions, assuming that the other side of the House acts in union. With several serially rebellious MPs on its own benches, that will undoubtedly happen from time to time as it did for John Major and James Callaghan, the most recent prime ministers to govern with little or no majority.
Yet when it comes to the big questions â€“ matters of confidence and supply â€“ rebellions do not happen and the Conservatives should be secure. Unless that majority starts dwindling. Will it?
There are two principal causes for losing MPs: by-election defeats and defections. On the former, one notable trend over recent decades has been the diminishing number of by-elections. There were only five by-elections in the last parliament in seats won by a governing party at the previous election, of which two were called following defections. This compares with 19 during the previous decade, 63 in the 1960s and 70 in the 1950s. If that trend is maintained then Cameron will not lose his majority even were the Conservatives to lose them all, which is itself improbable.
Itâ€™s true that the Conservtivesâ€™ by-election record in government is nothing special but we should be wary of projecting results from the 1990s, when Labour was thirty or more points ahead in the polls, onto the present. Milibandâ€™s Labour never achieved that sort of lead and it seems improbable that Corbynâ€™s will either. The Lib Dems or UKIP might pose a stronger threat but unless the government makes an almighty mess of it then safe seats should still be held.
So what of the other cause: defections? Much again depends on the popularity of both the Conservatives and the party the MPâ€™s joining: rats do not join a sinking ship â€“ or even one that looks of dubious seaworthiness.
But not all defections are a matter of expediency, or at least, not solely. Usually there is some element of policy disagreement or personality clash in the mix too, pushing the MP out. And hereâ€™s where the big risk lies for Cameron. The last three Tory MPs to defect all went to UKIP. Given that the EU referendum will inevitably result in deep divisions within the Conservatives, can he prevent more from following suit, particularly if the renegotiation results â€“ as seems likely â€“ in him recommending a â€˜status quo plusâ€™ rather than a significantly different form of membership? With UKIP likely to be the only party of any size recommending withdrawal, links will no doubt be forged out of necessity on the campaign trail. A victory for In, particularly a narrow one regarded by Sceptics as having been won by deception, media bias or some other form of jiggery pokery, may well extract a very high political price in the Commons.
Thatâ€™s not to say it will happen. There are plenty of â€˜ifâ€™s to line up first (though thereâ€™s also more than one route to the same end). But nonetheless, itâ€™s far from impossible that the Conservatives could lose their majority by midway through the parliament.
On that score, both 2018 and 2019 look like good value for the year of the next election, at 12/1 and 10/1 respectively with SkyBet. Not only is there the risk of the government being brought down having lost its majority, thereâ€™s also the possibility that it may seek to force an early election itself if events develop more benignly. Thatâ€™s harder under the Fixed Term Parliaments Act but still achievable, particularly if thereâ€™s no viable alternative government available. A new PM may well try to seek his or her own mandate in the way that Gordon Brown nearly did; all the more so if Labourâ€™s alternative is regarded as unelectable.