All area senators voted for the legislation, except Robert Menendez (D., N.J.) and Pat Toomey (R., Pa.), who voted no.
The plan has to navigate a difficult road in the Republican-dominated House. Many lawmakers in both chambers still see ending Saturday delivery as an important, timely, and necessary cost-cutting move.
The Postal Service has been struggling, battered by the 2007-09 economic recession and customers' increasing reliance on electronic communication. Postal officials have proposed several strategies, including ending Saturday service and studying whether to close about 3,700 of the nation's 31,509 post offices, and consolidate or close 234 of the 431 processing facilities. Many of the targeted post offices are in smaller, more rural areas.
The Government Accountability Office, Congress' investigative arm, estimates that the Postal Service has lost $25 billion since 2006. Going to five-day-a-week delivery would save about $3.1 billion a year.
The Senate plan would bar the Postal Service from ending Saturday delivery for at least two years. Cutting six-day-a-week service would be the last option. If the Postal Service could not save money any other way, and the GAO agrees, Saturday service could be ended.
Closing post offices still would be difficult, because the bill would require postal officials to work with local communities before closing a facility. Any closing could be appealed to the Postal Regulatory Commission, a five-member panel appointed by the president and subject to Senate confirmation.
The Senate bill would save an estimated $19 billion by 2016, when it's fully phased in. Among its changes: It would be easier for the Postal Service to end door-to-door service in limited instances. It also would have two years to implement cost-saving changes, notably a workforce reduction of about 18 percent, or 100,000 jobs. They could be offered buyouts or retirement incentives.