In book 2 the United States loses the ability to feed its population due to coastal flooding and a rapidly expanding ice sheet. The President of the United States makes a request to the President of Mexico: sell the United States 15,000,000 acres of Mexico’s farmland. Mexico’s President Ibarra initially threatens to build a wall to keep American farmers from entering Mexico. However, after the United States stations 15,000 troops on the border, Mexico relents and sells the requested farmland.