Despite his history of donating to Republican campaigns, billionaire philanthropist Charles Koch won't be contributing money to any of the Republican presidential candidates.When asked by ABC News if he's supporting Donald Trump or Ted Cruz, the Koch Industries CEO responded that unless they change some of their positions, he's sitting this one out.He called Cruz "frightening" and said Trump's ideologies were "reminiscent of Nazi Germany."He may reconsider his stance if Cruz takes back his plan to carpet bomb ISIS or Trump changes his policies on immigration. But as of now, he said, he and his brother David "haven't put a penny in any of these campaigns, pro or con."And this is coming from someone whose political organization was planning to spend $889 million on the election, according to the New York Times . What made the brothers change their minds?"These personal attacks and pitting one person against the other — that's the message you're sending the country," he explained. "You're role models and you're terrible role models. So how — I don't know how we could support 'em."He said he and his brother prefer to "build alliances to make the country better."Trump is currently leading the Republican race with 845 delegates. Cruz is at 559. A candidate needs 1,237 to get the nomination.