Earlier this month, the German news magazine Der Spiegel published a series of articles revealing that a German source was behind erroneous information about mobile chemical weapons factories in Iraq under Saddam Hussein.

The information, famously used by Colin Powell in his 2003 speech to the UN laying out the Bush administration's case for war with Iraq, came from an Iraqi refugee to Germany, who was given the retrospectively ironic codename "Curveball."

Curveball claimed to have been a chemical engineer but was actually a fake. Nonetheless the German Intelligence Service, the BND, passed on what he said to Washington. Was this a case of Germany publicly opposing the war while placating the US behind-the-scenes by providing the Bush government with a pretense for commencing hostilities?

The vice-chairman of the Bundestag's Supervisory Committee for the BND, Free Democrat Max Stadler, is one of the parliamentarians who will try to resolve that question. But, as he told DW-WORLD.DE, answers and possible action are a long way off.

DW-WORLD.DE: Who is the committee planning to interview in this affair?

Stadler: No one. The way this committee works is that the government reports on all matters relevant to the German Intelligence Service. The Curveball affair attracted a lot of attention in the press so that will, of course, be part of the report. We aren't having witnesses testify. That right is reserved for a special investigations committee, not the supervisory committee.

The Spiegel report gives the impression that the BND gave Washington information it suspected might be unreliable. Is that your impression as well?

That's precisely the reason, in my opinion, that the affair needs to be taken up in the supervisory committee. This impression has in fact been made in the press. On the other hand, the reports also state that the BND under the previous German government sent a letter to the effect that the information from Curveball hadn't been checked out or confirmed by a second source. The letter said, insofar as I understand it, that [the German government] could not guarantee the information was reliable. The committee is going to take another look at that. But what you said about the general impression one gets from the media reports is correct.

Lawrence Wilkerson, the chief of staff to former Secretary of State Colin Powell, has accused the BND of hindering CIA attempts to question Curveball and of therefore being partially responsible for the Iraq War. That's a fairly serious charge, isn't it?

I don't know precisely how things developed. I'll have to wait for the hearing next week before I can say anything about that. But I would say, generally speaking, that the Iraq War was a long time coming. Much of the opinion in the US had been formed before the Curveball testimony. I personally cannot imagine that one intelligence report from Germany would have been the all-decisive factor for the American government back then.

German officially refused to join the US-led coalition in Iraq. But reports repeatedly surface about Germany sharing intelligence with the US and thereby helping America in that conflict. Does that amount to taking part in the war via the back door?

That's precisely what the BND investigations committee is looking into. The issue came up two years ago, when it became known that two BND officials were active in Baghdad. The government said they were acting in the national interest. But the government also said the officials reported back information to their central headquarters that was then passed on to the Americans. The government says that's perfectly normal. My personal opinion is that this does represent, if only marginally, an intervention in the Iraq War -- and it certainly contrasts with what the previous SPD-Green government was telling the public at the time. And precisely the question of whether the government said one thing while doing another will be a question for the investigation committee. Germany's participation may have been slight, confined to the passing-on of information. But when you consider how heavily the governing coalition back then featured opposition to the war in their election campaign, the two things don't really add up.

What can the supervisory committee do, if it concludes that the BND or the government acted improperly?

In principle, the supervisory committee is pledged to secrecy. Even in cases of impropriety, we aren't allowed to make public statements. But there is an exception. If two-thirds of the committee members think it's necessary, we can issue a public evaluation. Members of the opposition parties, though, are not particularly happy about this rule. We think members of opposition parties should have also have the opportunity to issue dissenting evaluations. But we'll see after the meeting whether there is a two-thirds majority for making such a public statement.

So the basic function of the supervisory committee is to make recommendations to the government.

Yes, our recommendations go straight to the government and are not usually made public. But recently the committee has made more and more use of the two-thirds option. And that could well be the case again.

Generally speaking, intelligence services -- and especially US intelligence services -- didn't do a very good job getting quality information about Iraq. How can this situation be improved so that in the future we don't wage war because of non-existent weapons of mass destruction?

I think it's high time that politicians recognize that intelligence services have a servile function. They're supposed to deliver information that makes it easier to take decisions. But the politicians are the ones who ultimately have to decide. And maybe they should treat the analyses they get from intelligence services with a bit more scepticism -- instead of using them as excuse by saying "We had no other options given the intelligence at our disposal." Ultimately, politicians are always free to make up their own minds.