Re: Jesse Levine
I don't see Levine as being very useful as a Davis Cup player while we're in the World Group. He doesn't do well against top 50 players - he has won just twice in 28 matches against a top 50 player in his career (0 for 8 in 2012). Pospisil, on the other hand is 4 for 10.
But he could be useful for World Group play-offs, when the competition is lower ranked.
I wonder whether part of his motivation for switching is to get a WC into the Masters event, which comes with a nice pay cheque.
BTW he is now listed as Canadian on the ATP site.