In a televised interview last night, Mr Kohl conceded for the first time that the two biggest parties might be condemned to govern together. "I consider a grand coalition to be possible in principle, because democrats have to be able to form coalitions with each other," the Chancellor said.
In the glacial world of German politics, this admission of political reality was treated as a sensation. Christian Democrat spin doctors scrambled to issue "clarifications", urging editors to take a closer look at the rest of the interview, particularly the part where Mr Kohl declares: "I will not be the leader of a grand coalition."
Until now, the Chancellor's strategy consisted of presenting Sunday's elections as a choice between himself, or a coalition of Social Democrats and Greens. Gerhard Schroder, the Social Democrat challenger, had always denied that. He had shown willingness to deal with anyone but the post- Communists of eastern Germany. In a television interview on Monday night, he even suggested he was prepared to play second fiddle in a government led by Christian Democrats.
With the polls consistently predicting an extremely close race, a marriage of convenience has always been regarded as one of the most possible outcomes of Sunday's vote. Never has an opposition party come to power in elections in post-war Germany. Willy Brandt became the first Social Democrat chancellor in 1969 after serving three years as junior partner to the Christian Democrats.
With such a precedent, Mr Kohl is understandably not keen to repeat the experience. After the last "grand coalition", the Christian Democrats were out of power for 13 years.
But this time the prospect of such a government is seen as the logical outcome of the blurring of the differences between the two great parties. After six months of campaigning, the voters can be excused for feeling a little confused.
With Chancellor Kohl, at least they know where they stand. After 16 years of "stability and peace", the incumbent is promising four more. At the hustings, Mr Kohl runs through his achievements, drops a few promises about trying to bring down unemployment and reform taxation and plays on his image as the trusted pilot in stormy seas.
The Social Democrats, on the other hand, speak with forked tongues. Leftists, such as the party chairman Oskar Lafontaine, hark back to the values of traditional socialism: safe jobs, safe pensions and lots of child benefits.
This is the mantra that Mr Schroder adopted for his rallies, whilst his real message, about the need for "structural reforms" in the welfare state and jobs market, is being delivered surreptitiously.
The differences between the Kohl product and the Schroder vision boil down to style. Mr Schroder, 54, plays pop and jazz at his rallies, while Mr Kohl's crowds are warmed up by oompah bands.
The real choice is between change, offered by Mr Schroder with a nudge and a wink, and permanence, which the Chancellor has written all over him. That much Germans understand, but how those contradictions could be resolved in a joint government, nobody can fathom.