The megadonors drew the president's ire after Charles Koch said at a donor retreat in Colorado that their network wouldn't necessarily oppose all Democratic candidates exclusively because of their party affiliation.
The president's harsh words for the powerful brothers came a day after they signaled an intention to shift away from their practice of pushing for Republican-only bills and policy solutions, saying they would seek and push bipartisan proposals, which is seen as a repudiation of Trump. "I never sought their support because I don't need their money or bad ideas", Mr. Trump wrote Tuesday morning.
"Their network is highly overrated", Trump said. And little more than three months before Election Day, it leaves a top-tier Republican Senate campaign without the assistance of one of the conservative movement's most powerful allies as their party fights to maintain control of Congress.
Charles Koch himself stopped short of blaming the president for the partisan rancour.
"We support policies that help all people improve their lives", James Davis, a spokesman for the Koch network, said in a statement.
Trump held a rally in Tampa on Tuesday in a show of force for DeSantis, who faces off against state Agriculture Commissioner Adam Putnam in the state's August 28 Republican primary. But he embraced Trump's moves during the first year of his presidency, including the $1.5 trillion tax package Trump signed into law late last year that instituted a 40% permanent tax cut for corporations.
The Koch network also ran ads against Republican House lawmaker Lou Barletta of Pennsylvania for wasteful spending, telling the Philadelphia Enquirer it chose to target races where it thought it could "elevate" the spending issue.
"The Kochs had zero to do with Trump's win in 2016", former White House counselor Steve Bannon told the AP.
Other Republicans said they were optimistic that the warring wings of the party could reconcile before the elections, in which the GOP is trying to stave off a possible Democratic wave.
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. "They have always been more libertarian independents".
The Koch network is only active in four Senate races, including Wisconsin, Tennessee, Florida and Missouri.
At the same time, Bevin defended Trump's push to apply billions of dollars in tariffs on goods from China, Canada, Mexico and the European Union.