Could a Tory deal with Lib Dems really deliver stable government?

Sean O'Grady finds the cracks in David Cameron's proposals

The Tories must be serious about it because figures such as William Hague have started calling the Liberal Democrats by their correct title rather than just "the Liberals". Nice to see him acquire some manners.

More substantively, there are three tests for such an arrangement. First, could an informal or full-blown coalition actually agree a joint programme? Second, would the two parties' MPs and supporters wear it? And three, would it actually work? All, that is, in the context of an apparently more juicy offer of a referendum on electoral reform from Gordon Brown.

On the first test, someone in the Tory leader's camp had obviously gutted the two parties' manifestos and picked out the bits that are more or less common to both: government by Venn diagram.

On a cynical reading, then, David Cameron merely picked out the parts of his party's programme that the Liberal Democrats agree with anyway. Cynical, you might argue, and slightly underestimating the Liberal Democrats' intelligence. Still, Mr Cameron's "big, comprehensive and open offer" does highlight genuine agreement on important policy areas: education and the "pupil premium"; the "low-carbon economy"; the restoration of civil liberties and the cancellation of identity cards. Mr Cameron might also have thrown in the way that Vince Cable and George Osborne agree on breaking up the banks, and how both parties want to devolve more power to local government.

Yet, all this low-hanging fruit for a joint programme is essentially secondary. As Gordon Brown says, the most crucial, pressing areas for agreement are on fixing the economy and fixing the political system, which includes electoral reform.

Vince Cable has been conspicuous by his absence recently, for whatever reason, but it was glaringly apparent from the Cable/Osborne/Alistair Darling televised chancellors' debate that on the timing of public spending cuts and narrowing the budget deficit, Labour and the Liberal Democrats are far closer together than either is to the Conservatives.

Both agree with many independent economists that the immediate action on reducing the budget deficit the Conservatives insist on – as Mr Cameron did yesterday – would endanger the recovery with no commensurate benefit in market confidence. In other words, Vince doesn't want to cut £6bn from public spending now, whereas George emphatically does. Mr Cameron was right to pick out the Liberal Democrats' aversion to the "tax on jobs", but he left out that they are committed to it for the time being, ironically because they want to put cutting the deficit before tax cuts. Putting Vince Cable into No 11 merely to carry out Tory policy was not what Mr Cable was put on Earth to do.

As Mr Cameron said that he was prepared to give ground generally, it may be that the parties could split the difference on the £6bn cuts this year that the Tories want; £3bn might be taken to be less of a risk to recovery, and yet still seen by the markets as a token of longer-term determination.

Second, of course, is electoral reform. The best Mr Cameron could offer was an all-party committee of inquiry into the possibility of reform. Perhaps a commitment to a referendum might follow, but as it stands Mr Cameron's offer is inferior to that of Tony Blair in 1997, which was never delivered. The Liberal Democrats are right to say that, for a century now, successive speakers' conferences, independent inquiries and party reports have led to precisely nothing. A commitment to referendum might well be dragged out of Mr Cameron, and maybe a free vote in the Commons, though no doubt he himself will retain his personal opposition to change. A clever option for Mr Cameron would be to tempt the Liberal Democrats to self-destruction by offering a referendum on the most extreme variant of PR used in the world's most dysfunctional democracies. We shall see; but here again movement and compromise might move things along. That may also be possible over Trident, immigration and Europe, but it is a little difficult to see how the parties would navigate those particular thickets.

Would Tory and Liberal Democrat MPs support the joint programme? Here Nick Clegg might find things uncomfortable. To do a deal he needs to persuade a majority of his MPs. Otherwise a painfully cumbersome process of party consultation is required. This is the so-called triple lock. The rule was passed at the 1998 Liberal Democrat conference, and designed to block any sell-out of the party by Paddy Ashdown to Tony Blair. As it is effectively part of the British constitution it might be worth quoting it in full:

"In the event of any substantial proposal which could affect the Party's independence of political action, the consent will be required of a majority of members of the Parliamentary Party in the House of Commons and the Federal Executive; and

ii) unless there is a three-quarters majority of each group in favour of the proposals, the consent of the majority of those present and voting at a Special Conference convened under clause 6.6 of the Constitution; and

iii) Unless there is a two-thirds majority of those present and voting at that Conference in favour of the proposals, the consent of a majority of all members of the Party voting in the ballot called."

Provided Mr Clegg can win the backing of his MPs he need not ask the wider membership, who might oppose it. One way or another Mr Clegg would be faced with a nasty split. Many Liberal Democrats have spent decades fighting the Tories. To now ally the party to the old enemy would stick in many, many craws. Mr Clegg will find it hard to persuade them that Mr Cameron's Tories are a progressive party. Mr Cameron would have more success with his own party, and might not mind if the Liberal Democrats did split over the deal. After all, they have been trying to woo some of the more economically liberal "Orange Book" Liberal Democrats for years.

Last, would the programme work? Even if the polices adopted were sound and popular, the tensions between the parties and their supporters would probably be fatal. A messy divorce would be inevitable, and the Liberal Democrats should recall that Mr Cameron retains the right to call an election at a time of his choosing. He would like his own majority, and fundamentally that means putting the Liberal Democrats to the knife. Not a marriage made in heaven.