Leading article: The truth on trial

As much as with Margaret Thatcher and the Falklands, Britain's role in the Iraq conflict has been personally identified with Tony Blair. He often referred to it as "my decision", and did so again in his evidence to the Chilcot inquiry on Friday. Yet one of the important themes emerging from the inquiry is the extent to which the Iraq war was a collective enterprise.

This newspaper, which opposed the war more strenuously and consistently than any other, has always tried to avoid the simple view of the decision-making process as that of an over-mighty prime minister riding roughshod over a supine Cabinet and a feeble House of Commons. Mr Blair was the principal architect of British policy – even if the original mover of the invasion was George Bush – but he was not an absolute monarch.

It ought to be one of the functions of the Iraq inquiry report, which Sir John Chilcot said on Friday that he hopes to publish at the end of this year, to name the other guilty parties. Sir John did say at the outset that his committee "cannot determine guilt or innocence", but he went on to say: "We will not shy away from making criticisms where they are warranted."

The inquiry has heard more than enough evidence to know that criticisms are warranted. In particular, the new information about the way in which the legal case for war was constructed has vindicated the stance taken by The Independent on Sunday from the start.

This was not Mr Blair's responsibility alone. Geoff Hoon, the Defence Secretary; John Scarlett, chairman of the Joint Intelligence Committee; Sir Richard Dearlove, head of MI6; Alastair Campbell and Jonathan Powell, at No 10; they all played their part. But Jack Straw, Foreign Secretary, and Lord Goldsmith, Attorney General, were two of the main villains of the piece. Mr Straw, who returns for a second session at the inquiry next week, seems to have regarded it as his job to insulate No 10 from the lawyers in his department, knowing that all 27 regarded military action in Iraq as contrary to international law. Once Mr Straw had lectured his own lawyers on how he knew the law better than they did, and had been proved right in the courts when he disagreed with the lawyers at the Home Office, he turned his attention to writing a long letter to Lord Goldsmith.

The Attorney General, we now know, thought that military action required further United Nations authorisation after resolution 1441. But then, after consulting Mr Straw and Bush administration lawyers in Washington, he changed his mind. Had he refused to do so, British forces would have been unable to join the invasion, whatever Mr Blair wanted.

The heroine of the story so far is Elizabeth Wilmshurst, deputy legal adviser to the Foreign Office until the invasion. As we reported exclusively last week, in holding that military action was illegal, she was far from the "voice in the wilderness" that she was presented as being by the Government. She was the only official to resign on that point of principle, and for that brave stand as much as for the integrity of her evidence she deserved her round of applause from the public gallery on Tuesday.

The position of her boss, Sir Michael Wood, was more ambiguous. He thought the war was illegal, and said that his advice had not been overruled before, but he stayed in post. He also told the inquiry that someone at No 10 had asked, "Why has this been put in writing?", when he submitted a paper on the consequences of going ahead without legal approval. That is a damning indictment of the way that the inner court operated.

The political case for war was no more robust than the legal case – although who knows what the attitude of the Cabinet would have been had they known how "finely balanced" the legal case was, in Lord Goldsmith's unheard words.

Here Mr Straw was arrogant enough to tell the inquiry that, had he opposed the invasion, Mr Blair would not have been able to persuade Cabinet and Parliament to back it. He is right, which should be a cause for shame rather than pride, a shame compounded by the way in which Mr Straw has consistently sought to suggest that he was less gung-ho than Mr Blair, as if he were trying to keep his options open in case another colleague discovered his principles.

That other colleague, of course, was Gordon Brown. His opposition would also have been sufficient to ensure that British forces would have stayed out of the war. He must be held to account for that decision when he appears before the inquiry in a few weeks' time.