The defection of Douglas Carswell and his (re)election as a Ukip MP in Clacton is a defining moment in modern British political history. His defection hit the Conservatives for six; then not long after, when another Tory, Mark Reckless, defected to Ukip at the start of the conference season, it just seemed to add insult to injury.
Now Reckless' by-election at Rochester and Strood on 20 November has been deemed a "must win" for Cameron; the message is that everyone who can spare the time is meant to do what they can to stem the threat of losing another "safe" Tory seat to a turncoat Faragist. The problem with this is that the polls locally are giving Reckless a decent lead. It looks likely that the Conservatives will then lose this seat as well.
Don't feed the crocodile
This fiasco can be laid at Cameron's door. The rise of Ukip in the last two years may have took everyone by surprise, but Cameron's strategy has been as transparently ham-fisted as it is self-defeating.
Eighteen months ago, Ukip was brought onto the serious political radar by their spectacular second-place at the Eastleigh by-election (they had had some similar - though less spectacular - results late in 2012). It was around this time that Cameron pledged to have an in-out referendum on the EU if Brussels refused to give in to his wishes for a renegotiation. This had no effect on stemming the leakage of voters to Ukip; if anything, their vote only increased with each sign of Cameron's desperation. With each passing phase of Ukip's growing appeal, Cameron is pressured into making more concessions to the Eurosceptic right of his party. Not for the first time, he shows himself to be a follower and not a leader.
The latest twist in this story became truly dramatic, when Cameron seemed to suggest a plan to limit the number of European migrants allowed into the UK. With exquisite timing, Manuel Barroso, the retiring EU bureaucrat rapidly smacked down any suggestion of Cameron's idea getting any leeway in Europe: simply, this idea broke one of the fundamental tenets of the EU, the free movement of labour.
Gleefully, Farage posted a twitter"thankyou" to Barroso for this helpful clarification, thus confirming everything that Farage has been saying all this time: that the only way to control Britain's borders was to leave the EU. There were no half-measures.
In fact, apart from all the other factors, the rise of Ukip must also be partly down to the fact that people know that Cameron's claims of being the only person able to reform the EU and give Britain a real choice are complete nonsense. Farage may also be one of the few leading politicians who can "talk human", but his words are also a lot more likely to be taken at face value.
Et tu, Brutus?
Now, after Cameron had a private meeting with MPs, Ken Clarke, the sole remaining moderate of the "old guard" still in parliament (and still respected), seems to have "gone rogue". Saying what probably many Tories think privately, he has suggested those Tory MPs with views more similar to those of Ukip would be better simply defecting outright and making things clearer for the "real" Conservatives - "Cameron's Conservatives".
Only a moment's thought about what this would mean in reality doesn't bear thinking about for Cameron. Some insiders have said that if (when?) the Tories lose the Rochester by-election to Ukip, it would encourage others to follow. Ken Clarke's words can only have added fuel to the fire. The last thing Cameron wants would be a civil war in the governing party little more than six months from a general election - but that looks a lot like what he's got.
We've been here before, and this is where Cameron's failings really start to show. John Major's seven-year premiership (1990-1997) was dogged by political in-fighting about Europe, culminating in the leadership challenge of John Redwood in 1995 (which resolved nothing). Major's premiership was characterised by his weak leadership, with him pleading in the weeks leading up to the general election with mischief-making Eurosceptic MPs not to "bind his hands" over Europe. But what Major faced then looks like a minor tiff compared to the naked schism on display today.
While Cameron's personality may have many differences to Major's, Cameron shares the same aimless, bland ideology of the "moderate" Conservative, and also shares the same tendency to let others lead the way on discourse and argument. What does Cameron truly believe in? Apart from his own self-confidence, few people can really say.
So Ken Clarke's "suggestion" looks like turning the Tories into little more than a vehicle for Cameron's facile and nameless "ideology" (something I alluded to last year), and a recipe for electoral disaster. This is ironic, given that people have in the past called Ukip little more than a bandwagon for Nigel Farage's omnipresent personality - Ken Clarke would do something similar to the old Conservative and Unionist Party, leaving the "real" Conservatives to join Ukip.