Revelations that German spies were providing information to their US counterparts ahead of the invasion of Iraq are threatening to shatter the centre-left's hopes of taking on Angela Merkel at next year's general election.
The charges – relating to two Baghdad-based German spies – were causing severe embarrassment for Frank-Walter Steinmeier, Berlin's current Social Democrat Foreign Minister who was only recently chosen as his party's candidate to run against the conservative Chancellor Merkel.
If proved, the allegations could wreck the 62-year-old Social Democrat's chances at the polls. In the run-up to the Iraq war, Germany, under its then Chancellor, Gerhard Schröder, vehemently opposed the impending invasion. He narrowly won the country's 2002 election as a result of his anti-war stance.
At the time Mr Steinmeier was chief of staff in Mr Schröder's office and co-ordinated the work of Germany's intelligence services. The suggestion emerging yesterday was that despite their anti-war rhetoric, Mr Schröder and Mr Steinmeier struck a secret deal with the Americans to provide them with target information supplied by German agents in Iraq which cleared a path for the US invasion.
The two German secret service (BND) agents have been named as Lieutenant-Colonel Rainer Mahner and Chief Superintendent Volker Heinster. Both appeared before a special parliamentary commission investigating the case yesterday after intelligence documents containing evidence of their alleged complicity with the Americans was leaked to the press. The hearing, which is expected to last months, was held behind closed doors.
However, Germany's Stern magazine, which published excerpts from the documents, argued that the two agents were "the physical embodiment of the lie perpetrated by the then Chancellor, Gerhard Schröder – the lie of no to the Iraq war – which he used to win the September 2002 election".
The two agents were in Baghdad before and during the initial stages of the invasion, between 20 March and 7 April 2003. The magazine said that as the Americans had no trained agents of their own on the ground, the two Germans "became the eyes and ears of the American superpower's war machine". After each US air raid, the Germans apparently toured the city reporting back to the Americans about the accuracy of their bombing.
Hans-Christian Ströbele, a Green MP taking part in the parliamentary inquiry, said he had seen some of the incriminating documents himself. "The two agents were deployed in Baghdad with the full approval of the Chancellor's office," he said. "They sent information that was important for the war via BND headquarters to the US military command centre in Qatar."
His remarks were echoed by MPs from Germany's liberal Free Democrat and Left Party who had also seen the documents. Mr Ströbele said that it was "beyond doubt" that the agents had supplied the Americans with map co-ordinates revealing the whereabouts of locations used by the Iraqi Republican Guard , Saddam Hussein and the positions of Iraqi army heavy machine-gun units.
He also said that written requests made by the Americans to the German agents had been "rendered 99 per cent illegible" in the documents. However, he said it had not been established whether Mr Steinmeier had been aware of the full scope of the agents' activities and that the BND men could have been acting without his knowledge.
Mr Steinmeier, who is due to give evidence before the parliamentary commission in November, has insisted that whatever the activities of the two agents, they were not enough to "turn Germany posthumously into a warmonger".