RANCHO MIRAGE, California — Three potential Republican presidential candidates appeared before a gathering of wealthy donors organized by the conservative billionaire Koch brothers in California on Sunday night. The summit, held at a luxury resort near Palm Springs sealed off to outsiders, drew Republican Senators Marco Rubio from Florida, Rand Paul from Kentucky and Ted Cruz from Texas. It was organized by brothers Charles and David Koch, successful industrialists who bankroll conservative causes across America. Access to their network of money and influence is alluring to some potential Republican presidential hopefuls. The Kochs have a private network that spent hundreds of millions of dollars in recent elections and a donor list that is wealthy, diverse and hungry for a Republican candidate that can win the White House in 2016. The Koch event capped a busy two days where the long road to the Republican nomination appeared to have begun in earnest. Eight potential Republican candidates made speeches at a separate gathering in Iowa on Saturday. At least a dozen Republicans are showing interest in 2016. Former Florida governor Jeb Bush and former Republican presidential nominee Mitt Romney are among those seriously looking at White House bids. Chris Christie, the Republican New Jersey governor, has formed a political action committee, a major step to a presidential run, the Wall Street Journal reported o. Sunday. On Sunday night, Republican senators Rubio, Paul and Cruz discussed domestic and foreign policy. They were being hosted by Freedom Partners Chamber of Commerce, a non-profit organization backed by the Koch brothers. Freedom Partners and other Koch political fundraising entities are structured under the US tax code so that their donors, and how much money they give, do not have to be disclosed. The political advocacy network run by the Koch brothers aimed to spend $290 million on advertisements and messaging ahead of the 2014 mid-term elections. The Koch brothers are frequently criticized by Democrats as being secretive bankrollers of Republican causes and campaigns. The press was not allowed access for the California gathering. Freedom Partners released excerpts of a speech by Charles Koch to attendees on Saturday night, in which he said “the struggle for freedom never ends.” An internet feed of the three senators' discussion was also provided. Lifting people out of poverty, and whether a federal minimum wage was a potential solution, particularly animated them. “I think the minimum wage constantly hurts the most vulnerable,” Cruz said. — Reuters