I think this is a great discision and I can't see it being motivated by politics at all. The US101 is an excellent helicopter, with a lot of power and plenty of space. Just what is required for Marine 1. The fact that is costs a fortune to run and is so large, may put off commercial operators, but for this sort of application, or for the Military, it is perfect.
What's more, you can't put the most powerful man in the world (certain amount of tongue-in-cheek required) in a totally unproven helicopter. Yes, the 101 has had its share of problems, but at least they are known about and there are tens of thousands of flights hours behind it. Not so the S-92 despite what Sikorski sales pitch will tell you. Having 5,000 hrs across 5 airframes, is not the same as having 5,000 hours on one airframe.
Well done to the 101 and may this contract be the source of many more orders.