Los Angeles (CNN)There are few endorsements in the 2016 presidential race that could have as much impact as that of the Koch Brothers with their expansive political network, their state of the art voter data and ability to flood the airwaves to help their chosen candidate -- or candidates.
'Koch primary' heads to California
So there are few events as important to the top tier of GOP candidates as this weekend's oceanside retreat with Charles and David Koch -- and the many donors who have helped build their sprawling political network.
Notably not on the list of invitees to the Orange County city of Dana Point: billionaire Donald Trump, who has startled the political establishment with his strength in national and early state polls.
Who made the cut? Not Trump.
Only those who "we feel are great policy leaders at the federal, state and local level" were invited, said James Davis, a spokesman for Freedom Partners, the non-profit umbrella group presiding over the Koch's political empire
The GOP presidential candidates running most strongly in what has become widely known as the "Koch Primary" -- former Florida Gov. Jeb Bush, Florida Sen. Marco Rubio, Texas Sen. Ted Cruz, Wisc. Gov. Scott Walker -- will all address the group and mingle with Koch-allied donors at this weekend's gathering.
Carly Fiorina, another candidate viewed favorably by the Kochs and their allies, will also speak to the group though she has yet to demonstrate the same kind of political strength as some of those other rivals in the polls. Kentucky Sen. Rand Paul, who has courted the Kochs over several years, was invited, but will not be attending because of other campaign obligations.
Davis noted that Freedom Partners sent out a detailed questionnaire to all the candidates earlier this year. The candidates invited to Dana Point, he said, have been "leading voices" on some or all of the issues that the Koch network cares most about: criminal justice reform, fiscal responsibility, their campaign against the export import bank and policy areas that they frame as "overregulation" and "corporate welfare."
It is still not clear whether the Koch Brothers will help one candidate, or several, or whether they will choose sides at all before Republican voters select their nominee next year. But the groups in their arsenal plan could spend hundreds of millions of dollars to shape the outcome of the election.
While it has been previously reported that the Koch's plan to spend as much as $900 million on the election in 2016, a June Koch Industries newsletter said that number had been widely misreported.
Freedom Partners, which is hosting the weekend gathering in Orange County, hopes to raise $889 million by the end of 2016, the newsletter said. Only about a third of that amount will be spent on "electoral efforts" such as presidential, congressional, state and local races. Individual donors within the network would decide "the total amount spent on the various elections," the missive said.
That is in part why the Freedom Partners gathering will draw a number of high profile governors and senators, some of whom are rising stars in the Republican Party. Among those taking part in the policy-focused panels throughout the weekend: Colorado Sen. Cory Gardner, South Carolina Gov. Nikki Haley, Arizona Gov. Doug Ducey, Illinois Gov. Bruce Rauner, Texas Gov. Greg Abbott and Indiana Gov. Mike Pence.
Previous retreats have been shrouded in secrecy and closed to the press. But this year for the first time, Freedom Partners is allowing a small group of reporters to cover the candidate events.
Democrats who spent millions of dollars in the previous two election cycles painting the Koch Brothers' agenda as harmful to the environment, American jobs and the livelihood of American workers, have impugned candidates who have sought alliances with the network.
While that battle over the Koch image continues on the airwaves, Freedom Partners is looking to publicize the work of its political organizations at the gathering this weekend, particularly, Davis said, the work of groups "advocating against policies that benefit the politically connected at the expense of everyone else in our society."