"We can't support him at this time", Tim Phillips, president of the Americans for Prosperity, the network's flagship political organization, said of the candidate, Republican Representative Kevin Cramer.
The Kochs were equally concerned about the Trump administration's "protectionist" trade policies, which have sparked an global trade war and could trigger a USA recession, Koch said.
"Heitkamp is seen as one of the most vulnerable Senate Democrats up for reelection", The Hill reported, noting that Trump crushed Hillary Clinton in the Roughrider State. Some of the network's biggest donors and most experienced activists are Trump's most ardent supporters. "We're gonna more directly deal with that and hold people accountable".
But this latest feud - following last weekend's gathering at which Koch-affiliated officials sought to distance their operation from Trump - has exposed the rift between a president pushing his party toward populism, and establishment Republicans espousing the long-standing policy of free trade.
"The Koch network has had tremendous impact on helping us who wanted to change the direction of the country a couple years ago", Sen.
Some Trump loyalists were furious at perceived contradictions in the Koch network's behavior and anxious that it could complicate the president's 2020 re-election.More news: Deadly Northern California wildfire grows by two-thirds overnight
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"Here's the program: Ground game to support Trump's presidency and program, [and] victory on November 6", Bannon said in an interview with POLITICO.
"That's not right", he told the Associated Press.
The Koch brothers' statements against Trump come less than 100 days before the midterm elections and could have a major impact. We do the ground game because we're not going to equivocate on who we're going to support.
Officials for the Koch network said that AFP is now involved in seven races this midterm cycle across six states: Wisconsin, Missouri, Tennessee, Michigan, Nevada and Florida. And they say they were willing to form alliances with Democrats to achieve top objectives.
John McConnell, who owns a Missouri-based company that manufactures laboratory equipment, said rising steel costs already have cut into profit margins. He said his policies "made them richer".
Trump's policies on trade in particular have provoked ire among some Republicans, especially those in states most affected by retaliatory tariffs enacted by China, Canada, the European Union and beyond.
Charles Koch, the chairman and CEO of the industrial conglomerate Koch Industries, oversees the network of about 700 donors.