I think it fair to say that Campbell's evidence to the two previous Iraq inquiries has not shed a great deal of light on the truth. His role, in particular, in the fabrication of the spurious WMD dossier, and his role in the death of Dr Kelly remain largely undiscovered territory. The question is whether his culpability is of a degree that would also compel him to lie to the Chilcot Inquiry when he gives evidence later today.
We are promised that Sir Roderic Lyne (BBC .mp3 profile, 13mts) is likely to be the toughest questioner that Campbell will face, and I suppose we must wait until this evening's news bulletins to find out.
There is genuine doubt in particular in the manner of Dr Kelly's death, with expert opinions emerging suggesting it's increasingly likely not to have been suicide. Blair, Campbell and the government of the day may not have commissioned Kelly's death directly, but I've got a gut feeling they know who did. In the murky world of politics these days in which the main parties are financed not by their members but by foreign governments and oligarchs, it is too easy for a complicit State or individual to secure a cover-up from both Conservative and Labour leaders.
These are deep waters in which the public interest, indeed the national interest, are unlikely to be well served by the political class.