The U.K.'s relationship with the U.S. has proved strong enough over time to bear the weight of honest disagreement. It does not require unconditional support where our interests or judgements differ.
The judgements about the severity of the threat posed by Iraq's weapons of a mass destruction - WMD - were presented with a certainty that was not justified.
Blair overestimated his ability to influence U.S. decisions on Iraq.
Despite explicit warnings, the consequences of the invasion were underestimated.