The fashion choice for the last 20 years or so for the APEC meeting of world leaders has been to wear the local dress. This has been the case since Bill Clinton dressed everyone in Leather Jackets and so the tradition continued through ponchos and silks and so on.
Strangely enough, Bush and Putin looked completely at ease in silk.
But his year, Obama has decided that tradition should not be carried out and so the Hawaiian shirts that they leaders would have worn should be put to one side and it will be business suits as usual.
Feel free to insert comments about Obama trying to be serious in this time of austerity, but dammit, I like watching them try to pull off fashion like only middle aged people can and its normally the best copy out of these meetings anyway.