Posted by Patrick Dunleavy.

All recent projections are pointing to a hung Parliament – where the top party in the Commons does not have an overall majority (that is, 326 or more out of the 650 MPs). But this term covers  two kinds of very different situations:

1. A shallow hung Parliament would occur if one party gets close to the 326 majority level but does not quite reach it. Bear in mind that for David Cameron, there are a cushion of Northern Ireland seats, with the Unionists of all persuasions likely to support him in office, and the Sinn Fein MPs certain not to show up at Westminster (and so not needing to be covered). These considerations suggest that the lower boundary for a Cameron government with a working ability to pass laws should be put at around 318 seats and not 326. From 317 down to 300 seats for the Conservatives, the Parliament would be shallowly hung – meaning that the Labour party and the Liberal Democrats together would not be able to bring it down on a motion of confidence. Cameron in these circumstances would very likely run a minority government, saying to the Liberal Democrats – “Support us or look unpatriotic, and risk another immediate election”. Given the concentration of executive power in ministers’ hands and the general uselessness of the Commons as any kind of effective legislature, a Conservative minority government is pretty certain to be able to last out until May 2011, when it would call a second general election.

2. A deeply hung Parliament occurs when both the Tories nor Labour get less than 300 seats, and so neither could hope to pass any legislation without seeking the active co-operation of the Liberal Democrats from the word go. They would also need something like a rock-solid coalition pact of the kind that are common in continental Europe, so that the government could reliably survive votes of confidence. How long such a pact would last could vary a lot – at least a year to May 2011. But perhaps a longer term might be agreed to try and give greater certainty to the UK’s public finances, here at least two years would be needed. At a limit, a coalition pact might be negotiated for a full Parliament of four years – the public interest logic being that getting the public finances right would take that long. The political logic would be that for whichever two parties are involved in a pact, the government would need to do painful things in their first two years in office, and would then need two more years to let the memory of all that pain recede into the past and good times roll for the next election.

So what are the prospects of a Tory-Liberal Democrat coalition government or pact in a deeply hung Parliament? They do not in fact look good, because the Conservatives will be entirely unwilling to make any concessions on constitutional reform that the Liberal Democrats must get from this unique post-war opportunity. The two parties agree about canceling the ID cards and about the need to be tougher in getting public spending definitively down to cut the government deficit. But in every other policy domain they are poles apart – and are seen by voters as very different (see David Sanders’ blog post). In addition, Cameron is already in a weakish position within his party under internal attacks from his right wing, which would escalate fast if he cannot win outright. So although Nick Clegg is attracted to working with Cameron, any Tory-Lib Dem pact is likely to be very short-lived and traumatic for both parties.

By contrast, a Labour-Liberal Democrat coalition looks much more feasible, if Labour could possibly just get the most MPs. Gordon Brown could stay in office and negotiate with Clegg a deal that brings at least 6 prominent Lib Dems into the Cabinet, possibly even with Vince Cable as Chancellor, Clegg as Home Secretary and Chris Huhn at Energy and Climate Change. The raw materials  for a Lib-Lab pact are lying ready. Labour has already accepted the Alternative Vote system for electing the House of Commons. Both parties will pledge a PR-elected Senate to replace the House of Lords in their upcoming manifestos. And PR elections for English and Welsh local government would almost certainly be thrown into the mix, following their successful  introduction in Scotland. This is the prospectus for a great reforming government according to Peter Hain, and the Labour Cabinet has already swung around to agreeing. A Lib-Lab government (on current polls) would also  have a clear majority of public support from the election, giving it the legitimacy needed to tackle the long-run actions needed on the budget deficit. It could decisively mark the point at which the UK becomes a normal European liberal democracy and when the incumbent political elites at last accept that the Westminster model of government is dead and buried.

So what could go wrong? Well there are plenty of tribalist MPs in both parties to cause trouble. And Clegg was previously convinced that he could not afford to prop up an unpopular Gordon Brown in office, nor to run the risks of trying to work with such a moody and strong-willed character in Number 10. The last risk is still there, but as Labour has improved its poll rankings and Cameron has been seen to flounder, so Brown is increasingly assuming in the public’s eyes the mantle of a plucky underdog who kept on fighting. All this makes him more potentially supportable by Clegg. Brown’s own position within Labour would be enormously strengthened by staying in office, while the Byers/Hewitt/Hoon scandal has already carried off the last of his Blairite critics into ignominy.