If ever there were two countries with a truly "special relationship", they are Germany and Israel.

For obvious reasons of history, they are bound together. The genocidal madness of a previous generation of the one and the suffering of the victims of a previous generation of the other make them intertwined in a way no other two countries are.

But is the relationship changing? There are certainly signs that it is being re-examined in Germany. What was taken as a given in the past is now up for questioning.

Two very prominent intellectuals, for example, have recently questioned whether Germans have been constrained from saying what they mean or from doing what they should because of guilt.

It is true that the Nobel Prize-winner, Guenter Grass, and the best-selling author and former member of the board of the Bundesbank, Thilo Sarrazin, do not represent the country - but their controversial views do seem to resonate with some.

Nuclear dilemma

What was once unsayable in Germany now plays in the public discourse.

The relationship between Israel and Germany has also surfaced in a report by the magazine Spiegel about submarines which Germany produced (and supplied on very generous terms) for the Israeli navy.

The reputable magazine says it has evidence that the submarines can be armed with nuclear warheads - and that the German government knows that.

This raises the question, as the magazine puts it: "Should Germany, the country of the perpetrators, be allowed to assist Israel, the land of the victims, in the development of a nuclear weapons arsenal capable of extinguishing hundreds of thousands of human lives?"

It has no answer - but others do. Mr Grass wrote a poem which was widely condemned for comparing Israel and Iran, but it did raise the question of whether Germany should be helping Israel in its use of nuclear weapons. The issue was put into play.

As he put it in the poem, the submarines have the ability "to direct nuclear warheads toward an area in which not a single atom bomb has yet been proved to exist", namely Iran.

In the German collective psyche (at least at an official level), two things have underpinned policy: a support of Israel - but also an aversion to war, particularly where mass death might ensue.

The question increasingly asked in Germany is: Does the first aim conflict with the second?

Words weighed

The former German Chancellor Helmut Schmidt once said he was unhappy with Chancellor Angela Merkel's statement in 2008 that Germany bore responsibility for the security of the state of Israel.

Rather, Mr Schmidt said, "Germany has a special responsibility to ensure that such crimes as occurred in the Holocaust never occur again. But Germany has no responsibility for Israel."

In Germany, every official utterance is weighed for nuance. Words matter. The debate broke to the surface in Germany with the Spiegel article and also with a state visit to Israel by the new president of Germany, Joachim Gauck.

President Gauck is a man who speaks his mind - he came to the post not through a conventional political background but as an activist against the old communist regime in East Germany. He tends to say what he means (which may be why the politically astute Mrs Merkel was uneasy about him getting the job).

On a recent state visit to Israel, President Gauck spoke about the relationship - but didn't copy or echo exactly Mrs Merkel's words. Where she had said that the security of Israel was in Germany's national interest, he said, "Advocacy for Israel's security and right to exist is a defining part of German policy."

Can you spot any difference? Commentators in Germany thought they could. Was it a softening, they wondered, as the words were pored over syllable by syllable.

German unease

President Gauck denied it - "I completely agree with Angela Merkel on this issue." But the fine debate over the finest hint of a scintilla of nuance illustrates the sensitivity.

As well there might be. A poll conducted by the respected Forsa institute just before the visit indicated rising German unease with Israeli government policy.

According to the poll, 60% of Germans believe that their country has no special responsibility toward Israel because of the Holocaust, in contrast to only 33% of those questioned who thought that Germany does have a special responsibility.

On top of that, the poll indicated that 70% of Germans believe Israel pursues its interests without consideration for other peoples.

It should be said that neither Mr Grass nor Mr Sarrazin is a member of the government, elected by the will of the people. They speak for nobody but themselves - and the government and all the mainstream parties remain utterly committed to Israel.

The submarines illustrate that - and there are more to come.

As though to allay German unease, Israeli Prime Minister Benjamin Netanyahu took the trouble to give an interview to the editors of the Bild newspaper this week - he talked through its pages directly to the German people.

He said about Chancellor Merkel: "I take her commitment to Israel very seriously. There is a commitment to Israel's security that is exemplified by the recent sale of another German submarine, an important adjunct to our national security, so I believe this is all real and tangible.

"But as far as Israel's defences, we have never asked for other countries to come and physically defend us."

He added: "While I appreciate Germany's concern for Israel's security the most important assistance that can be given to Israel is - to paraphrase Churchill - to give us the tools and we will do the job of defending ourselves."

That's what Germany is doing. But Germans are debating it.