Just a guess, but it seems that this more than grand theft, more than practical joke. It feels like it was his way of playing “dare, double dare.’ It was his way of dissing an American big shot and a symbol of something that is uniquely American, an institution that not only Mr. Kraft, but Americans in general hold dear. It’s time for him to say something nice about Mr. Kraft and the Patriots and to return the ring to its owner, Mr. Kraft. He shouldn’t wait for Donald Trump to make it happen. He should do it himself, voluntarily, even though mighty late.
Who knows what Putin’s motivation was/is.
It is customary for gifts to be exchanged as tokens of appreciation, to heads of state.