If the US makes a law that ConAgra does not like, ConAgra could refuse to sell any seeds in the US or any of her trade partners for ONE year. If that happens, our nation will suffer unimaginable famine, as will all of our trade partners, because 'terminator seeds' produce plants that are sexually inert. In one year, ConAgra could break every developed nation in the world due to its hold on our foodstuffs.
GM corn experiments involving inducing male sterility in humans were entirely successful when they were conducted a few years back. Similarly horrific experiments have taken place.
Furthermore, the only salable benefit to GM foods is the increased material output, but that output comes with a compensatory reduction in nutritional value, therefore nullifying any apparent benefit.