Jay Allen is a fan of President Donald Trump, and voted for him on the belief that the Republican would cut taxes and trim regulations, helping his manufacturing business in northeast Arkansas. But the tariffs at the core of Trump's economic agenda have wreaked havoc on his company, Allen Engineering Corp., which makes industrial equipment used to install, finish and pave concrete. The import taxes have raised the costs of engines, steel, gearboxes and clutches made abroad that Allen needs to build power trowels that can sell for up to $100,000 each.