Many Kansas farmers who voted for President Trump now know the pain of his agenda.

Tariffs on imported steel and aluminum previously pursued by the president and directed at China hurt the heartland, as commodity prices tumbled. Retaliatory measures by targeted trade partners too often punish U.S. agricultural producers who depend on those markets.

Trump made matters worse by also targeting the European Union, Canada and Mexico, which had been exempt from the steel and aluminum levies. Naturally, they’ll fight back with duties on imports from many American businesses and farmers.

Such negative fallout was inevitable, yet Trump charged ahead. The Republican celebrated as a business whiz may understand casinos and real estate development — and, of course, the benefit to billionaires of massive tax cuts — but appears clueless when it comes to world commodities and a complex trading system.

Trump’s steel and aluminum tariffs previously levied on China alone were bad enough for Kansas, the nation’s leading sorghum producer. China has been a top foreign market for U.S. sorghum growers.

The president only piled on the damage by bullying still more important trade allies.

Sadly, his rash, shortsighted acts are eerily reminiscent of former Gov. Sam Brownback’s many miscalculations. Brownback’s economic blunders scarred Kansas, and Trump’s escalating trade war will do the same in a state where he was enthusiastically supported at the polls.

Farmers in Kansas understandably became fed up with Brownback’s radical income tax-cut approach that saw funds diverted away from roads, public schools and other programs vital in rural parts. Now they must endure direct hits on their wallets by Trump, a Brownback ally who’s eagerly pursued policies bad for the Sunflower State.

While protecting American aluminum and steel interests is a reasonable quest, there’s no sense in disproportionately punishing other business sectors and agricultural interests.

The goal should be thoughtful consideration of ways to build on existing trade and new opportunities — not plowing ahead with a win-at-all-costs mentality that will weaken agriculture.

Kansans in Congress — including U.S. Sen. Pat Roberts, chairman of the Senate Agriculture Committee — had best start making headway in minimizing the irrefutable damage of a growing trade war Kansas farmers and the state cannot afford.