The Conservatives are fighting the final days of the election campaign on two fronts.
One is about arithmetic. If the sum of parties that would vote down a David Cameron government ends up being greater than the sum of those that would vote in favour of one, then the prime minister will lose his job.
The second front is about which is the largest party and goes beyond the result of Thursday’s election. The aftermath of a vote that could see the leader of the second largest party in No 10 is already raising questions over the legitimacy of such a government.
This debate is getting louder by the day and could lead to months, if not years, of finger-pointing, accusations of squatting in power and calls for a new election. In the row over legitimacy, the relative gap between the two largest parties will matter – and could sway a public already inclined to believe that the leader with the most seats has the bigger mandate to govern.
The challenge for the Tories is this: for every seat they lose to Labour they need to gain two seats elsewhere to make up for the shortfall. And when it comes to the party’s various options that fundamentally means Lib Dem-held seats. The potential Tory gains from Ukip and in Scotland are rather limited.
It is in this particular arena that the south-west is one of the election’s key battlegrounds. How results play out here will go a long way in determining if the Conservatives emerge as the largest party, and that is why the Tories are battling so hard to take seats from their coalition partners in their heartland.
On Tuesday, David Cameron was in St Ives, north Cornwall, warning voters that a vote for the Lib Dems risked uncertainty and a government dominated by the SNP.
The Lib Dems hold 15 seats in the region. Based on current polling, Nick Clegg’s party is expected to lose nine of them, eight to the Conservatives.
In all six seats the Lib Dems are expected to retain, the Tories are in second place. In the closest of these races, in constituencies such as North Cornwall, Cheltenham and St Ives, Ukip is still polling in double figures.
While the prime minister was in the south-west, Iain Duncan Smith, the work and pensions secretary, warned that a vote for Ukip could hand the election to Ed Miliband.
Tuesday's Telegraph (Scotland) - Sturgeon: Tories will have no mandate to rule us #tomorrowspaperstoday #bbcpapers pic.twitter.com/Dmj8QOXGMX
— Nick Sutton (@suttonnick) May 4, 2015
The south-west may not provide Cameron with the seats he needs to stay in office. However, it may well give his party the extra ammunition it needs to fight the post-election legitimacy battle when – and if – it fully erupts.
