A top official with the Koch brothers is leaving his perch to join Florida Sen. Marco Rubio's presidential campaign.
Marc Short, president of Freedom Partners, the central organization of Charles and David Koch's political and strategic network, will be a senior adviser to Rubio effective immediately.
The Kochs, wealthy billionaire activists, have spent hundreds of millions of dollars in presidential politics - including $400 million in the 2012 election. While they have not directly engaged their vast donor network in the Republican primary, signs indicate that they prefer Marco Rubio and are doing things short of directly spending money to help him.
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Representatives from the super PAC backing Rubio, Conservative Solutions, spent the night of Iowa caucus meeting with donors at the Koch donor retreat near Palm Springs, California.
And Short's move will give Rubio access to a vast network of wealthy donors. The Koch donor network consists of nearly 900 donors and have contributed an estimated $750 to $900 million for political and strategic goals in 2015 and 2016.
At the end of January, Rubio's campaign had $5 million dollars in the bank. He'll need an influx of cash as the primary moves national. Twenty-seven states and territories hold their contests by March 15.
"Marc Short has advised me that he is resigning effective immediately as President of Freedom Partners Chamber of Commerce. Marc has been a valued leader and contributor to Freedom Partners' and our network's success for the past five years. We thank him for his dedicated service and wish him continued success in the future," Mark Holden, chairman of the Freedom Partners board, said in a statement.
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The Kochs are vehemently opposed to Republican frontrunner Donald Trump. They have indicated their network could deploy its massive war chest to tip the scales against Trump in the primary, but no plans have been dispatched yet.
Rubio is one of five Republican candidates still in the Republican primary, but his path to the nomination is difficult. He placed third in Iowa, fifth in New Hampshire and second in South Carolina. He is behind Trump in the delegate count heading into Super Tuesday next week, when nearly 900 delegates are up for grabs.
This article first appeared on NBCNews.com.