You get some wonderful things under Freedom of Information. Overnight, the US National Security Archive (a private organisation, despite its official-sounding name) has published a set of PowerPoint demonstrations released by the Pentagon, which provide a fascinating insight into planning for the Iraq war.

We already knew that the Bush administration was the captive of rosy scenarios. But there’s nothing quite like seeing them set out this way. Donald Rumsfeld’s staff believed “a broad-based, credible provisional government” would be in place for the invasion, the post-hostilities phase of the operation would last only for “months”, and (as The New York Times puts it) “Iraqi Army units would heed the American appeals to stay in their garrisons and later help United States to secure the country.”

Designing a war by PowerPoint is a surreal idea. The NSA press release quotes one of the planners, Lt Gen David McKiernan: “In lieu of an order, or a … plan, you get a set of PowerPoint slides … [T]hat is frustrating, because nobody wants to plan against PowerPoint slides.”

Just as past revelations have had little impact on the pro-war lobby, it’s unlikely that these will either. We will be told that the mistakes of the past are irrelevant, and we need to focus on what’s happening today. Even if you opposed the war in the first place, they say, you can still accept that premature withdrawal would be a disaster.

There’s an element of truth in this. The rights and wrongs of the invasion are logically separate from the question of current policy.

But when the people directing current policy are shown to have been so spectacularly wrong in the past, it deals a powerful blow to their current credibility — particularly when they offer no explanation or apology.

Our own John Howard just this week doggedly maintained that the decision to go to war in the first place was correct. When someone says that, how can you believe anything else they say?

If George W Bush were to come out and say, “OK, we made a dreadful mistake, we’re sorry, but now we need everyone to pull together and help fix it”, he might be worth listening to.

Until he does, we can be confident that nothing has really changed.