My use of the term 'formality' was in respect of it being a solely an issue to start the war and not to provide long term justification for it.

Had Blair and Bush said they were invading Iraq due to it being run by a despot, they would have to invade almost all of the middle east as well as N. Korea. Using WMD provides an easy reason, which have been a formality, for war. However, once the French and Russians began shouting and screaming, the use of WMD as the catalyst for the war became a big issue.