Before election day, a lot of column inches and airtime will be expended on discussing what the impact of a hung parliament would mean for British politics. Will the Liberal Democrats suddenly become essential to governing, raised from the relative parliamentary irrelevance of third party status to holding the balance in a divided parliament? Will domestic politics be targeted by a new generation of pressure groups, eager and empowered to influence the political horsetrading that would inevitably flow from the whips desperate struggle to get the government’s legislative programme through? Will politics in Britain become far more like that of our American cousins, with accusations of pork barrel activities designed to persuade wavering legislators to support a particular bill?

Less attention has been given to what the impact might be on foreign policy, and our ability to commit British troops to conflict should the need arise.

Many in the BBC and other media organisations have repeatedly made the error of describing the war in Iraq as a decision to ignore the will of the cabinet and parliament – in fact the decision to go to war was, for the first time in British history, subject to a clear ‘yes’ or ‘no’ vote in parliament, a vote which could have brought down Tony Blair’s government had he been defeated. Labour has promised to subject any further military interventions to a parliamentary vote in future, and a future Conservative government would be under great pressure to do the same. In a hung parliament, that could well mean that the Liberal Democrats have crucial votes which could affect the outcome, if there wasn’t a consensus between the two main parties on taking action.

One could imagine a situation where Labour sought to take action to intervene to protect citizens who were being ethnically cleansed, but a coalition of Conservatives and Liberals sought to diplomatically appease those involved, much as the Conservative government did in the Balkans in the 1990s. It is worth remembering that while the Iraq war had the legal basis – albeit disputed – of security council resolution 1441, there was no similar UN resolution supporting military intervention against Slobodan Milosevic.

It would be a constitutional crisis, given that traditionally it has been the prerogative of the monarch, and in reality her prime minister, to take ultimate responsibility for committing British troops to battle. Some might argue that Blair, having sought the will of parliament for the action against Saddam, has been held more personally responsible for that action than any of his predecessors.

Could we really have a situation where there was an urgent need to take military action (for instance, intelligence that pointed to the development of a nuclear weapons programme in Iran, which required an immediate strike by coalition air forces) but we lost the ability for any British involvement in a first strike because it would need to be publicly debated between the three parties in parliament?

Of course there has been a generally well-respected tradition in Britain of private and public co-operation between the parties on matters of national security. But the issue of Iraq drew a sharp dividing line between the Liberal Democrats and the two main parties. Could America really rely on Britain as a critical ally against al-Qaida or other extremists if discussions on defence and security policy were subject to the kind of political horsetrading that would affect domestic policy in a hung parliament? Is the world a safer place if security decisions of the British government become subject to the political positioning of small minority parties?

America of course faces a similar situation in its constitutional structure, with power vested in the congress to approve major military action. But in a culture which only has space for two political parties, getting consensus is far easier than it would be in Britain, with a third party that has been wary of taking military action in recent years.

In the event of a hung parliament, a new set of rules will need to be agreed between the parties to enable the government to take swift action to protect British interests in the event of a major security threat.

In the aftermath of Iraq, and in the discussions that will take place in the event of an unclear general election result, that will be a particularly tough challenge to overcome.