Why was the Karmapa's US tour cancelled?

My views on the Government of India's refusal to let the Karmapa leave for America have been published in Sify.com. Click here to read.
Yesterday a friend commented on my remarks about a successor for the Dalai Lama. He rightly said that the Tibetan movement will need a charismatic leader when the Dalai Lama goes (hopefully, he will be here for a long time). I agree with him, but there is still an ambiguity between a 'selected' successor and an 'elected' Kalon Tripa (Prime Minister). The solution is perhaps to have the Karmapa elected as next Kalon Tripa. Why not?