The one case they often use is Cardoen, who was an arms smuggler (working out of Chile), who claimed that he was secretly working for the CIA. He tried to export various weapons components (zirconium for cluster munitions, switches from ISC, and modified helicopters from a field in the Dallas area) from the US. He was caught and tried (and convicted). While using the "CIA" defense in court, he relied on an affidavit from Howard Teicher. This was a mistake for Cardoen, since even though Teicher's claims were based on classified NSDDs, the government prosecutors still had partial access to them and could prove the claims false (which, now that they are declassified, anyone can). Cardoen was convicted; the claims of US backing were shown to be false in a court of law (with a Clinton administration prosecutor, I might add).
Of course, that doesn't stop the left from insisting that Cardoen was a CIA operative. But now that the NSDDs have been declassified (they dealt with nuclear weapon stockpiles, and had nothing to do with Iraq), it can easily be shown that it was all based on a lie (not that the proof has stopped the left from still using the same lie).
When NSDD-26 was declassified, Teicher changed his story a bit, and instead of it being that document during the Reagan administration, it was instead NSD-26 from the Bush era. The only problem with that story is that Teicher had already left the NSC by the time that that document (which he earlier claimed to have authored) was produced. In further discount of his claims, NSD-26 is now also available to the public. Contrary to the left's lies that it showed "secret" support for Iraq's chemical weapon program, it instead insisted that Iraq be told that "any illegal use of chemical and/or biological weapons will lead to economic and politic sanctions". The only content relating to support for Iraq was "economic and poltical incentives for Iraq to moderate its behavior", a policy that, while stupid (it involved a lot of guaranteed agricultural loans that Iraq mis-used to buy weapons from other parties), had nothing related to the bogus claims of the left that we somehow armed Iraq.