Mr Kinkel, in an interview with the Suddeutsche Zeitung, argued that Mr Heitmann's fate was uncertain, even at the hands of Mr Kohl's party, despite receiving official approval this week. 'I have the impression that the CDU-CSU (the bloc consisting of the Christian Democrats and their Bavarian sister-party) is becoming unsure, and is having second thoughts.'
Wolfgang Schauble, one of the most important figures in the CDU, suggested last weekend that the Christian Democrats and the opposition Social Democrats may seek a joint presidential candidate. This was interpreted as an attempt to dump Mr Heitmann, Justice Minister of the east German state of Saxony, whose apparently right-wing statements have unleashed much controversy in recent weeks.
Mr Schauble was, however, forced to retract his implied criticism: Mr Kohl, whose will is rarely successfully challenged in the party, is determined that Mr Heitmann shall win through. (Mr Kohl described criticism of Mr Heitmann and his views as repugnant.)
This week, when Mr Heitmann appeared before the CDU and CSU to receive their official blessing, he appeared to make a positive impression on MPs, despite the adverse publicity.
Mr Kinkel yesterday insisted that 'the last word has not been spoken' on the question of the presidential race. The Free Democrats, the junior government coalition party led by Mr Kinkel, has officially nominated one of its own members, Hildegard Hamm-Brucher, after failing to persuade the former foreign minister, Hans-Dietrich Genscher, to stand. (Mr Genscher would easily have won if he had decided to be a candidate.) But Mr Kinkel still seems ready to dump Ms Hamm-Brucher, if a joint presidential candidate (neither Mr Heitmann nor Mr Hamm-Brucher) can be agreed. Asked about this he said: 'We are open for talks.' One possible joint candidate could be Roman Herzog, chairman of the constitutional court.
The defenders of Mr Heitmann, an east German pastor, suggest that he is much misunderstood. Certainly the picture is confused. His statements on the role of women were widely interpreted as a get-back-to-the kitchen message; but his wife, a sculptor, does not fit into that mould.
Mr Heitmann has been praised by extreme-right groups for saying that Germany must set aside guilt about the Holocaust; and yet, in the same interview, which caused enormous controversy in Germany because of its alleged attempt to sweep the past under the carpet, he spoke of the uniqueness of German crimes, including the 'organised death of millions of Jews'.
His critics suggest that the sharpness of his views will divide the nation when unity is badly needed. The current President, Richard von Weizsacker, has been widely praised and will be a difficult act to follow.
Mr Heitmann, meanwhile, remains unpopular: one recent poll suggested that he had only 4 per cent support in west Germany; the Social Democrats' candidate, Johannes Rau, polled 20 per cent. Even in the east, there is little sympathy for him (more than 60 per cent think he should stand down as a presidential candidate).
Public support is not essential for Mr Heitmann's victory, since the election of the president is by regional and federal MPs, not by popular vote. But if Mr Kohl succeeds in forcing his candidate through it may do him little good in the parliamentary elections a few months later.
Disenchantment with established politicians is enormous, and the to-ing and fro-ing over the presidency has not helped. One poll suggests that four in five Germans want direct presidential elections, so that they can choose for themselves, for the first time.