The Koch brothers' campaign arm is helping the Wisconsin state senate campaign of Dale Kooyenga, who plans to implement a flat tax that would hurt working families.

The campaign organization financed by the billionaire right-wing Koch Brothers is investing in the election of a Wisconsin Republican backing increased taxes for the poor.

State Rep. Dale Kooyenga is running for the seat in Wisconsin Senate District 5. His opponent is Democrat Julie Henszey.

Dark money group Americans for Prosperity (AFP) has announced they are financing a “six-figure” campaign to back Kooyenga and other Republicans in the state. The group will pay for canvassing and phone banking in support of Kooyenga.

Eric Bott, who is the Wisconsin state director for AFP, said in a release that Kooyenga’s support of “pro-growth reforms,” the term conservatives use to describe economic policy tilted toward the wealthy, was a key factor in their support.

David Koch co-founded AFP, and along with his brother Charles, has contributed millions of dollars to its deceptive campaigns to elect Republicans to office. Together, the Kochs have tried to push an agenda de-regulating industry and tilting fiscal policy toward the most wealthy.

Not coincidentally, the Kochs head businesses that have incurred massive fines for pollution and reportedly have personal fortunes of at least $50 billion each.

Kooyenga recently bragged in an interview that a “flat tax” would be a priority in the next legislative session if he is elected.

He tried to pass similar legislation in the past year, but it did not advance. Kooyenga has admitted that his plan would eliminate many tax credits that benefit middle-class families. If he had his way, Wisconsinites would lose marriage credits, tax credits for renters, and tax credits targeted at working families.

Conservatives have long promoted flat taxes, despite the fact they increase financial burdens for the poor and middle class while reducing the money the wealthy payd into the system.

The program that Kooyenga wants echoes the flat tax implemented in Illinois by that state’s Republican governor.

The Chicago Sun-Times editorial board noted the system “hits taxpayers at the low end extra hard because they must spend a larger share of their income on necessities, such as rent and food and diapers for the baby.”

After increased sales and payroll taxes are factored in, the paper explained that “the percentage of income a working woman or man pays in overall taxes is much higher than the percentage paid by a wealthy person.”

In stark contrast to Kooyenga and his dark money backing, Henszey is on record supporting state legislation for an amendment to overturn the Citizens United decision.

That Supreme Court finding allowed dark money groups like AFP to work as a conduit for billionaires to spend as much money as they wish to sway elections.

The Koch brothers want figures like Kooyenga working for them in the state senate, and his plan to increase tax burdens on the poorest are a key element in that strategy.