THE GERMAN ELECTION is on September 18; the British Conservative Party will vote on September 27 on a proposed constitutional amendment that might decide who is to be the next leader. The two events could be connected. If Angela Merkel, the Christian Democratic Union leader, becomes Chancellor, she will have won as a free-market reformer. If she loses, German voters will have repudiated radical reform.

She has even adopted Paul Kirchhof’s flat tax proposal. Hundreds of tax allowances and multiple tax bands would be replaced by a flat levy of 20 or 25 per cent. “Instead of needing 12 Saturdays to fill out a tax return, the new system would need just 10 minutes,” said Professor Kirchhof. “I want to give voters back their freedom by letting them decide what to do with their money.” This is Gladstonian finance; he wants to let money “fructify in the pockets of the people”.

At present most people assume that the Conservative Party will meekly agree to return the choice of leader from the membership to the parliamentary party. This is what Michael Howard, the present leader, has proposed; it is supported by the mysterious, and largely unrepresentative, board of the Conservative Party. The effect would be to reduce the leadership electorate from 250,000- 300,000 party members to 198 MPs. Trust the professionals; do not trust the people.

There would be no votes from the big cities, Birmingham, Bristol, Leeds, Liverpool, Manchester, Newcastle or Sheffield. There would be one vote from Scotland and three from Wales. Women would have 17 votes. That the board supports this shows its lack of political judgment; that it should be proposed by the leader and the parliamentary party suggests that too many of them are are not real democrats, or even good politicians. The Conservative Party needs mass support; this is the way to alienate the public.

Fortunately, amendments to the Conservative Party’s constitution require a two thirds majority of the MPs and a separate two thirds majority of the constituency chairmen and local association officials. It is not certain that either group will produce the majority needed.

There has, however, been a widespread expectation that the party, which has a traditional respect for authority, would do what it was told. The leadership debate, so far, has been conducted on the assumption that it would be an insider’s debate, that the MPs would decide. As a result there has hardly been any debate at all.

The Conservatives have only once had a democratic leadership election. That was in 2001, when the membership chose Iain Duncan Smith over Kenneth Clarke by a substantial majority. Mr Duncan Smith won the public debate, despite being by far the less impressive speaker. The members decided that they agreed with his Eurosceptic views, and disagreed with Mr Clarke’s Euro-enthusiasm.

In a leadership contest, whatever the system of election, the Conservative Party almost always chooses the candidate who is seen as right of centre inside the party. In the past 50 years, only Edward Heath won the leadership as the left-of-centre candidate. Macmillan, Douglas-Home, Thatcher, Major, Hague, Duncan Smith and Howard were all regarded as right of centre when they were chosen. This is still the pattern now, both inside the parliamentary party and, probably, in the membership. If so, the choice of system will not necessarily decide the outcome, but it will decide whether the new leader has the authority of a democratic vote, and it will shape the character of the debate.

At present, the majority of MPs belong to the moderate Right. In a parliamentary vote, one could expect David Davis to win against David Cameron or Mr Clarke. If there is no real debate, only cautious sparring, this is what will probably happen. I still doubt whether Mr Clarke will stand: Europe, tobacco and age all tell against him. I would regard Liam Fox as the probable reserve leader of the centre Right. David Cameron, however, is a serious candidate. Someone else may emerge, but has not yet done so.

The common assumption is that Mr Davis is stronger among the membership than among the MPs. If so, that means that he is stronger in the country, an important factor in itself. A democratic election by the whole membership would produce a democratic debate, which has not been happening so far. Both Mr Davis and Mr Cameron have been engaging in image politics; their speeches are not bad, but they glide away from the more difficult issues. They do not want to lose support by saying anything that will upset people.

This is where Angela Merkel comes in. If she wins, there will be new hope for conservative politics throughout Europe. But she will pose a difficult question for all conservative contenders in Europe. Are they prepared to tackle social expenditure and taxation? These big issues have defeated the Blair-Brown Administration. Of course, if Frau Merkel fails, every other European conservative will be running for cover, but we shall know that well before September 27.

So long as they only have to debate before their parliamentary colleagues, I would not expect any of the leading candidates to take a view on the flat tax issue — it is far too easily misrepresented as another kind of poll tax. Mr Davis would prefer to remain the great unifier; Mr Cameron would prefer to remain the socially responsible moderniser. In a genuine national debate, I believe that they would be forced to define their positions — that is one of the advantages of democracy.

Perhaps we have reached this paradoxical position: it is the modernisers who have been afraid of the membership (they have sometimes seemed afraid of modernisation itself), yet it would now take a real national debate to give the modernisers a chance.

Times Recommends

• Five golden rules for regulating banks
• Uighurs’ cry echoes round the world
• It is not just democracy that is illegal