Dr Helmut Kohl's continued refusal to name secret donors to his Christian Democrats (CDU) has ensured that the scandal surrounding anonymous cash payments to the party will rumble on for months, damaging the party's standing and undermining public confidence in the political process.

An attempt at the weekend by Dr Kohl's successor as CDU leader, Dr Wolfgang Schauble, to focus on the party's policies on tax and education was lost in a cacophony of rumours of internal splits, intrigues and leadership challenges.

The former chancellor has admitted accepting up to u1 £1 million in cash between 1993 and 1998 and channelling the money through a network of secret accounts to local party organisations. Dr Kohl insists he did not benefit personally from the donations and that the money did not influence government decisions.

But he acknowledges that his actions were in breach of Germany's party funding laws, which demand that donors of sums greater than u8000) £8,000 must be identified in party accounts. Prosecutors are investigating whether Dr Kohl is guilty of a criminal breach of trust by misusing funds that should have been lodged in his party's official accounts. Looking at the scandal from an Irish perspective, it is tempting to draw comparisons with allegations of corruption against our own politicians, notably the former Taoiseach, Mr Charles Haughey. But at first sight, the distinctions between the two cases are more striking than the similarities.

A man of modest habits who lives in a nondescript bungalow in his home town of Ludwigshaven, Dr Kohl shares few of Mr Haughey's lavish tastes in clothes, pictures or racehorses and no questions have been raised about the source of his personal income. Indeed, the former chancellor was notorious during his time in office for complaining about his meagre fortune and his lack of opportunity to provide for a more comfortable retirement.

But the two men shared an approach to political leadership that involved tightening their grip on their party organisations by binding allies in personal loyalty and eliminating rivals swiftly and ruthlessly. Like Mr Haughey, Dr Kohl identified himself and his own interests with those of the party he led for 25 years and, particularly in recent years, with those of the state itself.

For much of his career, the former chancellor was widely regarded as a plodding, machine politician, long on cunning but low on vision, who remained in power chiefly by virtue of the weakness of the Social Democratic opposition. His management of Europe's biggest economy was so hands-off as to be almost invisible and he did nothing to alleviate the sharp rise in unemployment that left four million Germans out of work by the time he left office in 1998.

His foreign policy achievements were more impressive, binding Germany firmly into the western alliance and pushing forward the process of European integration, regardless of domestic political considerations. By keeping his nerve despite loud opposition and an unpromising economic landscape, he ensured that Germany was ready to join the euro on schedule and that the new currency could be launched successfully a year ago.

But it is his role in unifying Germany that will secure Dr Kohl's place in history, regardless of the outcome of the investigation against him.

By seizing the historical moment of the collapse of communism in East Germany and persuading the former Soviet leader, Mr Mikhail Gorbachev, to agree to unification, Dr Kohl transformed the shape of Europe.

Germany's Social Democrats were lukewarm on unification up to the very moment it became a reality and, even within the chancellor's own party, many regarded his push for unity as hasty and unwise. It is more than likely that, without Helmut Kohl's leadership, the two Germanies would not have united, Russian troops would still be stationed in eastern Germany and the young democracies of central and eastern Europe would remain within Moscow's sphere of influence.

In view of these achievements, many CDU activists are outraged at the spotlight now being trained on their former leader's financial dealings and by the lack of support for Dr Kohl from the party's leadership. But as the shock of the initial revelations subsides, the broader German public is determined to find out more about the role of secret money in the running of Dr Kohl's government.

The former chancellor has, by his own admission, broken laws on party funding that he introduced himself and violated the constitution he vowed five times to protect. By cheating on the rules of party funding, he effectively rigged the electoral contest to his own advantage and shored up his position in power.

But Dr Kohl's refusal to name the donors - ostensibly because he is not prepared to break the promise he made to them of confidentiality - has left a number of important questions dangerously open. Until we know who gave him the money, we cannot tell why they gave it - or how much was given. Nor is it possible to test the former chancellor's claim that the donations never influenced government policy.

Dr Kohl has admitted accepting donations between 1993 and 1998 but he has not spoken about his financial dealings during his previous 10 years in office. His silence also leaves unanswered the question of how the money was and to what extent it helped the former chancellor to destroy rivals in the CDU who were preparing to move against him in 1987 and 1989.

While Dr Kohl remains silent, his party is tearing itself apart and Dr Schauble's position as leader looks increasingly precarious. From his position on the backbenches, the former chancellor still commands the loyalty of many within the CDU who are keen to topple their leader - perhaps at April's annual conference.

Dr Kohl's refusal to leave the limelight following his loss of power has hampered Dr Schauble's attempts to stamp his authority on the party. And much as they admire his achievements as a statesman, many within the CDU are convinced that Dr Kohl's continued presence in parliament can only damage the party and prolong the agony that has been caused by his own misdeeds.

The sooner Dr Kohl tells the full truth about his secret accounts and departs the political stage for good, the better it will be for his party, his country and his own place in the history books.