According to an article from Wired, the State Department is indicating that they may be considering more secure methods for adding RFID capability to the US Passport.

The current frontrunner is an idea called BAC (Basic Access Control) that will require reading of a key from the inside of the passport by a scanner in order to be able to retrieve data from the RFID chip.

Although not my preferred contact-based mechanism, it does appear to be a simple and effective modification to the existing mechanism that would require physical access to the opened individual passport for scanning.