As reported by the Los Angeles Times, Jack Nicklaus has a motivation beyond pure politics for supporting Romney in this year's election: regret.
When Gerald Ford ran against Jimmy Carter in 1976, he asked for Nicklaus's support and involvement during the campaign. Nicklaus, in an effort to remain neutral, turned his friend and golf partner down.
“He asked me to get involved and I didn’t,” Nicklaus said. “I said, ‘Mr. President, I’ve always stayed away from politics. I deal with people on both sides.’ And he respected that and he never had an issue with that, and we played a lot of golf after that. But I didn’t help him and he lost Ohio by several thousand votes. Had he won Ohio, he would have won the election. I’ve always had big regrets about that."UPDATE: according to uselection.org
“In spite of me not doing that, he paid me a great honor: I was a pallbearer at his funeral. He was such a good friend, such a nice man. That’s why I’ve gotten involved.”