INDIAN WELLS, CALIF. - The political network backed by conservative industrialists Charles and David Koch plans to spend $20 million to promote the tax overhaul recently signed into law by President Donald Trump.

The investment marks an early focus of the Koch brothers’ 2018 political strategy. It comes as the conservative billionaires work to expand their sweeping efforts to promote a “free society” in America.

Charles Koch and his chief lieutenants previewed their strategy on Saturday, the first day of a three-day private donor retreat at a luxury resort in the California desert. They previously announced plans to spend between $300 million and $400 million on politics and policy heading into the midterms when the GOP’s House and Senate majorities are at stake.

‘Increase the scale … 10 fold’

At an evening welcome reception, Koch called on his biggest donors to “increase the scale and effectiveness of this network by an order of magnitude — by another 10 fold.”

“If we can do that,” he said, “I’m convinced we can change the directory of this country.”

In addition to roughly 550 donors in attendance, each pledged an annual donation to the network of at least $100,000, the guest list featured a slate of Republican elected officials: Arizona Gov. Doug Ducey, Kentucky Gov. Matt Bevin, Sens. John Cornyn of Texas, Thom Tillis of North Carolina and Todd Young of Indiana, and House Freedom Caucus chairman Rep. Mark Meadows, R-N.C.

Despite Koch’s optimism, there was concern about the midterm elections. Historical trends suggest that GOP majorities in the House and Senate could be in jeopardy, said Tim Phillips, who leads the network’s political arm, Americans For Prosperity.

‘Energized’ left

“The left is energized,” Phillips said, noting that the party that holds the White House typically loses congressional seats in its first midterm election. “You’re going against the tide. You’re going against history.”

For now, at least, the conservative powerhouse will focus on the tax overhaul to help protect the Republican majorities. Phillips said the Koch network would host rallies and phone banks and run television and internet ads in the coming months.

“Our job is to make sure we shine a spotlight on those benefits that are occurring because of this law,” Phillips said. “Over time, that should overwhelm what has been a lot of demagoguery and rhetorical nonsense.”

Several reporters, including one from The Associated Press, were invited to attend some of the forums in the private weekend retreat. As a condition of attending, reporters were not permitted to identify any donors without their permission. No photographs were allowed.