Aside from the several issues you raised which I personally think won't have any impact on this Tran matter, you are not "wrong" as long as you use the word "logical" in the sense that there are much more important things for the Diet.
But to increase the possibility of Oly medals is a non-partisan matter that'll enlighten whole Japan, its economical effect is rather positive and never negative.
Once the fear of "Tran's dual citizenship becoming a precedent" is decreased by enveloping it into the 2-years frame, there isn't anything written in the Japanese law to completely refuse the procedure (this I called literally logical).
And Tran won't be an opportunist because he'll have never asked or applied for this.
In fact Tran has only said that he'll leave the whole matter to the JSF.
It will be the Japan side asking him to skate for the country he has represented for some time.
ETA; Mousepotato, whose dual citizenship did you mention Yuko asked for? I've no knowledge about that.



I wanna see your face! 


Bookmarks