One of the underlying assumptions of polling behaviour is that, like homing pigeons, voters always return from whence they came when general elections come around.
Yes, they enjoy their freedom as they stretch their wings and soar about all over the political landscape, but when it comes to deciding who actually runs the country, they fly back to their familiar coup.
Judging by current polls, however, they’re cutting it fine.
Tuesday’s ICM poll showed a fifth of voters are still saying they will vote for UKIP (11 per cent) or the Greens (9 per cent).
So what happens if the Tories don’t manage to squeeze UKIP and convince a big chunk of disgruntled former Conservatives to return to the fold?
What if all the media beastings of Nigel Farage and his troops in recent weeks end up having little effect? Indeed, what if UKIP’s insurgency is a symptom of a structural change taking place in British politics rather than a cyclical blip?
For Labour, there are two windpipes to choke. Ed Miliband needs to retain those Lib Dem voters who have abandoned Nick Clegg since 2010 as well as stopping the Greens from becoming a permanent fixture on the party’s left flank. The Greens current polling is their best performance in 20 years.
We are at that point in the political cycle where people have started referring to the looming election in terms of weeks, not months. Admittedly there is still time for things to change, but what usually happens during the short campaign is the Lib Dems rise a few points, a result of voter frustration with Labour and Tory to-ing and fro-ing.
What is to stop something similar happening in May, only with UKIP and the Greens (not forgetting the SNP) benefiting instead of the shop-soiled Lib Dems? Indeed, what if reports of Nick Clegg’s demise are exaggerated and the Lib Dems improve their position too? This would put a very big hole in Ed Miliband’s electoral bucket.
All of which is to reinforce the self-evident fact that British politics is now in a highly volatile state. (Hence the proliferation of question marks in this piece).
So much so, that 2015 may well be remembered as the first election where it was the main parties who were squeezed by the political fringe, not the other way around.