Newt can't win for the same reason that Hillary won't win -- too much baggage. Voters want a new choice, not a has-been.
You would think everyone would learn these lessons by now...
1. Most of the electorate are sheep willing to be lead.
2. All your baggage out is an asset! No surprises in the 11th hour.
3. You have much time to compose a gracious and clever answer to any "supposed" baggage.
4. The media can be made to look foolish with proper planning.
And they're both plain unlikeable.