" 
 ::::::That passage doesn't necessarily say the date format can never be changed without strong nationalistic reasons or prior consensus. It can be read as stipulating only that the date format should be consistent throughout an article, not having one original format and another latterly added one, unless there are valid reasons to make it otherwise based on national factors; if the format change takes place consistently across the whole article, the guideline hasn't been violated. Perhaps we should consider rewording these clauses to be less vague? 
 ::::::Regardless, there's evidently a four to two majority in favour of the [Month] [Day], [Year] format; so, I will make the change revert my own 2009 edit, though I think it might be fair to see what more Ckatz has to say, if anything.   "