H.R.4236: To provide for the protection and the integrity of the United States mail.

Mail Network Protection Act of 2007 - Requires the U.S. Postal Service to bargain with unions representing career Postal Service employees before entering into a contract for mail processing, mail handling, or surface transportation of mail if the contract, in a 12 month period, would involve work that would otherwise be performed by those employees and either: (1) involve more than a specified amount of work time; or (2) cost over $5 million.