WASHINGTON

--The only way to reach Supai, Ariz., (population 208) is to hike or helicopter eight miles to the bottom of the Grand Canyon. The U.S. Postal Service delivers mail and supplies there three days a week--by mule.

Although the country's steepest canyon may be no match for the American mail carrier, our postal system does face a gaping threat from a huge hole of another kind: After several years of modest surpluses, the Postal Service lost $25.4 billion between 2007 and 2011, plunging $13 billion into debt.

That crisis threatens postal facilities across the country. For three years, business owners and residents in Easton, Md., have been fighting plans to close the U.S. Postal Service sorting facility there. If it closes, mail would be trucked 160 miles to a facility near Wilmington, Del., taking with it an estimated $19 million from the area's economy.

The Easton plant is one of 252 mail processing centers being considered for closure as a cost-cutting measure. More than 3,800 post offices are also on the chopping block.

Digging out of the financial chasm will require further congressional action, and lawmakers are considering several reform plans. As they do, members of Congress should make every effort to preserve this critical and beloved American institution. They can start by adhering to these three core principles:

Minimize harm. Reform efforts should attempt to protect economically and socially vulnerable communities like those on the Eastern Shore, as well as the 574,000 Americans who count on the Postal Service for good, middle-class jobs.

Address the real problems. Declining mail volume is a problem, but Congress should also reform or repeal burdensome legislative mandates, including a 2006 requirement that the Postal Service pre-fund 75 years' worth of retiree health benefits over just 10 years. This law placed an unprecedented financial burden on the Postal Service during the worst economic downturn since the Great Depression.

Refrain from additional burdensome mandates. Congress should give the Postal Service more flexibility, not less, by rescinding legal restrictions on the kinds of activities it can conduct. This will allow the Postal Service to create a business model for the 21st century--while retaining delivery services essential for the public good.