For days, heavy rains have mired the annual Burning Man festival in thick mud in the remote desert of Black Rock City, Nevada, stranding tens of thousands of attendees who nonetheless struggled to keep the party going. At least one person has died, and organizers announced yesterday that the traditional closing ceremony — in which the titular effigy is set ablaze — would be postponed from Sunday to Monday.

But as burners conserved food and water, preparing to begin an exodus as conditions allowed, two Republicans in congress said their misery was...