He couldn't have won but he could have done way better. Rather than flip flop on affirmative action (which pleased no one), he should have stuck to his guns, opposed affirmative action, talked about poor White people, said All Lives Matter, and been the anti-political correctness candidate. He would have at least broke 10% in the polls and probably won Oklahoma, come in second in Florida, and stand a good chance of winning West Virginia. Again, he wouldn't win the nomination but he would be more famous. Maybe people would actually take his threat of a third party run seriously (not that he'd win there either, but he could break 5%, maybe get Trumps endorsement if Cruz wins the GOP nom). Then he could write books, get a talk show. Which would all be pretty good, compared to reality where he is a total non-entity.
This. Also, run heavily in states like OK, FL, SC, and etc. A combination of the Schweitzer western vote and the conservadem/centrist vote in the South and Midwest would have been enough, especially if he only campaigned heavily in South Carolina and did OK there.