SAN FRANCISCO, CA - AUGUST 12:  Cartons of mail ready to be sorted sit on a shelf at the U.S. Post Office sort center on August 12, 2011 in San Francisco, California.  The U.S. Postal Service is proposing to lay off 120,000 workers in order to deal with an $8.5 billion loss this year that has the agency close to insolvency. The layoffs, if approved by Congress, would take place over the next three years.  In addition to layoffs, the Postal Service also wants to eliminate 100,000 jobs through attrition.  (Photo by Justin Sullivan/Getty Images)