Imagine it is the afternoon of Friday 7 May next year. The final results of the general election have been declared. Labour has lost its majority but, as the result of a recovering economy and effective campaign, has emerged as the largest party in a hung parliament. Unlikely, but let's keep going. Imagine it now has 295 MPs in the new House of Commons, 30 more than the Conservatives - even though the Tories have won a million more votes. Fifty-eight Liberal Democrats and 32 nationalist and Northern Irish MPs also occupy the green benches at Westminster. What should Labour do?
As Peter Kellner shows on page 28, although the Conservatives are at present on course to win a clear majority, the next election may well produce no clear victor; but hung parliaments come in various forms. The practical options will depend on the exact numbers. Which party will be the largest? How close are they to the 326 seats they need for an overall majority? How many Liberal Democrats have been elected? Until we know the answers to these questions, we cannot tell how strong or weak the position of each party leader will be.
However, wait-and-see is not good enough. For a start, the weekend after the election is the very worst time to start working out what to do. The main players will be physically and emotionally exhausted. Calm heads and clear thinking will be required at precisely the moment both will be nigh-on impossible. Moreover, any post-election deal will have the taint of anti-democratic arrogance unless the parties have given some idea of how they would react to an indecisive result. Voters deserve to know what they are voting for - not just in terms of manifesto policies, but in terms of what kind of government might emerge from a hung parliament.
The Liberal Democrat leader, Nick Clegg, has begun to clarify his position. On Sunday, he said: "The party which has got the strongest mandate from the British people will have the first right to seek to govern." This has been interpreted as an anti-Labour statement. It might not be. If the Tories are the largest party, Labour will plainly have lost the election. For the Lib Dems to prop up Labour in these circumstances would be to commit political suicide. The Tories would - and would deserve to - form the new government. In all likelihood, David Cameron would offer Mr Clegg a coalition; he would reject it; Mr Cameron would form a minority government and call, and win, a second election a few months later.
But what if the result is something like the unlikely scenario painted at the start of this leader? What if Labour remains the largest party, but falls well short of an overall majority? What then? Mr Clegg was not pressed on what he meant by the "strongest mandate": the most MPs (in this example, Labour) or the most votes (in this example, the Tories).
Assuming Mr Clegg accepts the convention that, until and unless our voting system is changed, what matters is seats, then he is saying if Labour remains the largest party it should have a shot at staying in office. Yet Labour could not govern for long without some kind of compact with the Lib Dems.
However, without careful thought and planning well ahead of the election, an agreement could come quickly unstuck, because there will be intense criticism that a discredited Labour Party was clinging desperately power, and that supine Liberal Democrats lacked the guts to eject it. The only way Labour could - and, indeed, should - remain in office for long is if it forms a partnership of principle with Clegg's party, as it should have done after the 1997 landslide election victory.
Such an arrangement could take the form of a full coalition but need not do so. More important are the details of the deal. Here is our proposal. The two parties should agree to govern for no more than two years, and to use the time to clean up and repair Britain's broken political system. The agenda should include a referendum on a new voting system, a reduction in the number of MPs, thorough reform of the House of Lords, legislation for fixed-term parliaments, stronger civil liberties, an enhanced Freedom of Information Act, and extra powers for the Welsh and Scottish executives.
What Labour and the Lib Dems could then say, together, to the electorate is: we shall spend the next two years making British democracy fit for the 21st century, and then ask the people to decide who should represent them in a fully modernised parliament. There will be other ideas about how such a pact might work; what is important is to start debating the issues now and rediscover our shared progressive passion for defending and expanding the power of the people.
