He already did that last year!
Last year. Kerry already said he's "one quarter Jewish," when for his whole political career he was wanting people to think he was Boston Irish. As I underdstand it, Kerry is actually predominately French and Jewish (I'm not aware if it's Ashkenazim or what variety) with a (SMALL) bit of Irish. Bluntly, he wants to be everything to everybody.
And Islamic at the same time. There is absolutely no duplicity that is beyond him.
He already did that.