Trump opened the door to cheap foreign beef for 90 days, and American ranchers say it could wipe them out.

• The deal lets 300,000 metric tons of ground beef in tariff-free, mostly expected from Brazil and Argentina.
• Ranchers say the timing is brutal — herds are already shrunk by drought and fires, and this kills the first decent profits they've had in years.
• Republican senators from ranch states, and even the Agriculture Secretary, were sidelined and are openly against it.
• A handful of meat packers like Tyson control the market on both ends, so cheaper imports may never reach shoppers as lower prices.
• Food safety is a real worry: China recently rejected Argentinian beef over a banned antibiotic, and Florida pulled a large shipment off shelves.

Outlook: Beef prices are unlikely to drop much before the midterms, and ranchers expect more small operations to quit.