...a job at the post office has been a ticket to the middle class and has provided a pension and medical care to retirees.

From How the Post Office Made America:

"Other critics warn that ceasing Saturday service will be the first step down an irreversible “death spiral.”...

For millions of workers, including veterans and African-Americans, a job at the post office has been a ticket to the middle class and has provided a pension and medical care to retirees. The Postal Service is the country’s second largest civilian employer, after Walmart."

How the Post Office Made America

By RICHARD R. JOHN

Published: February 8, 2013

The New York Times