Scott Kelly lectures in British Politics at New York University. His pamphlet “The slow death of the ‘Efficient Secret’: The rise of MP independence, its causes and its implications” is published by The Constitution Society.

The starting gun for the general election has now been fired, national campaigns have been launched and the protracted chess match over the leaders’ debates is approaching an end game. Yet, if we look back to the last election we can see that none of this activity matters as much as we might think. Despite the hype and the high viewing figures, the leaders’ debates had little impact on the actual election result. On the ground many candidates and activists reported that they never saw much evidence of Cleggmania. It may well be the temporary swelling of the Lib Dems’ poll rating reflected who people thought had won the debates rather than how they were actually planning on voting.

National campaigns, and for that matter, national party leaders are becoming less relevant to explaining election outcomes. What is of growing importance is what happens on the ground in each constituency. In 2010 seat after seat refused to conform to a uniform national swing as popular Labour MPs held on while unpopular ones lost badly. Perhaps the greatest evidence of the importance of individual candidates, local issues and local campaigning can be seen in the performance of the Liberal Democrats. Where a popular MP had retired, as in Harrogate and Knaresborough, there was a big swing to the Conservatives. Unpopular candidates such as buffoonish Lembit Opik and the appalling Dr Evan Harris were ejected from Parliament. We are returning to an age of local politics.

I have argued previously on ConservativeHome that the growing importance of a personal vote has helped to insulate MPs from pressure from the party whips. However, it also exposes MP to greater pressure when it comes to issues that have a disproportionate impact on their area or a key demographic, particularly during elections. A significant development in local campaigns is that many MPs and candidates, either willingly or under duress, sign pledges or make commitments on specific issues. Whether it be about the local hospital, airport expansion, HS2, or even membership of the EU, a national party policy stance no longer satisfies voters, they want MPs to make a specific commitments on those issues about which they most care.

The rise of local politics is now impacting national government, putting the key constitutional principle of collective responsibility under strain. In 2010 every Liberal Democrat MP returned to parliament had signed the NUS pledge to oppose higher tuition fees. When higher fees were introduced, several Lib Dem ministers abstained, including Vince Cable, the Secretary of State with responsibility for the policy.

Other ministers have refused to back specific policies because of the impact on their constituencies. For example, the Europe Minister David Lidington has threatened to resign over HS2, which would pass through his Aylesbury seat. Although he was away on official business at the time of a key vote in April 2014, Lidington told his local newspaper that he had “decided to abstain, but I have been and remain opposed to HS2”, a statement which would appear to breach collective responsibility.

The erosion of a constitutional principle is of more than just academic interest, it shows how difficult it is becoming for voters to reconcile the dual functions of a vote cast at an election – the choice of a local MP and, by extension, of a government. Throughout most of the twentieth century the dual functions of general elections was not seen as presenting much of a problem because strong political parties fused these two choices into one. The weakening of the party grip on MPs has led to divergence, ultimately creating an accountability gap – who are the electorate holding to account at an election, the government or their MP? It’s often impossible to do both. As a consequence we should at least consider pragmatic reforms that could help differentiate the local and national functions of MPs, an issue that becomes most acute when an MP becomes a member of the government.

Until the 1920s it was established practice that when an MP was made a Minister they would stand for re-election. The practice had its origins in the seventeenth century when, after the restoration of the monarchy, King Charles II sought to control Parliament through the distribution of paid offices. Parliament retaliated by requiring that paid offices could only be accepted if membership of the house was tested at an election. By the early twentieth century governments were keen to end this practice of confirmation by by-election, finally persuading Parliament to abolish it in 1926. Yet, while it had become unwieldy to implement, the practice had given voters an opportunity to pass judgement on whether or not they wanted their MP to hold executive office.

If new Ministers had to face their electorate against it would force them to publically deal with the question of how their appointment affected any commitments they had made to their electors in the past. While it is difficult to envisage any government agreeing to a reform that would vastly increase the number of by-elections, it does point to a potential benefit of introducing checks on ministerial appointments. If a new Minister had to be formally approved following a hearing of the relevant Select Committee, then this would potentially force them to confront the same issues, it may also make Prime Ministers think more carefully about the possible ramifications of particular appointments.

The BBC may well wheel out its Swingometer on election night in May but the truth is that a national swing is now a thing of the past. Local factors increasingly determine electoral outcomes. We need to look at ways of reconciling a local electorate to a national parliament.