Washington State (P) was a hop trust selling excess hop allotments pursuant to a U.S. Department of Agriculture order requiring hop growers to obtain federal allotments to market their hops. As late as June 1985, the USDA was considering changing the system, but substantial changes were not anticipated. P mailed invitations for bids on two pools one in 1985 and the other in 1986. The bids were received on June 16, 1985, and awarded to various farmers. On June 27, 1985, the USDA terminated its marketing order effective December 31, 1985. All of the Ds refused to perform the contracts. The trial court granted summary judgment to Ds, and that was affirmed by the court of appeals, which excused Ds' contracts by the rule of supervening frustration. P appealed.