He should be tried for war crimes for dragging the UK into a war on false pretences.
Blair was accused of misleading parliament over the WMD claims and there was a limited attempt to impeach him: https://en.wikipedia.org/wiki/Parliamentary_motion_to_impeac...
Also relevant with regard to war crimes is this recent uncovering: https://www.theguardian.com/uk-news/2025/dec/30/tony-blair-p...
(There's lots of various opinions given about Blair which are not really authoritative, such as: https://www.standard.co.uk/news/politics/tony-blair-iraq-gov...)
So this was purely a political move on the part of Blair to cozy up to the US. Maddening.