According to an article on Wired (and Slashdot) the US State Department is planning on embedding RFID chips in passports. To me, this is more frightening than pretty much any other anti-privacy initiative taken by the government, because it would allow them to quite easily monitor all international movement of US citizens.

When I travel abroad, I usually take both passports, using my Japanese passport to enter countries (simply because I look Japanese to most people and get less crap), and my US passport for returning (because it's illegal to do otherwise). Right now, the US government has no record (apart from passenger lists -which they can not legally obtain by default) of a US citizen named Ryo Chijiiwa going anywhere... only that I returned at some point. But, with RFID, they (both the host country and, by extension, the US gov't) can scan the data off my US passport at foreign airports even if I don't present it to customs. They can keep track of all the countries I've visited, without my consent or knowledge.

Also, the way they're going about this is nothing if not suspicious. So they're saying:

"The reason we are doing this is that it simply makes passports more secure,"

But...

the U.S. government decided not to encrypt the data because of the risks involved in sharing the method of decryption with other countries.

So, if you want a secure passport, you put unencrypted data on a chip that can be read remotely, says the US government. How much dumber can these people get? I'd never given getting rid of my US citizenship much thought, but if this goes through (and apparently there's no way contest this) it might be the straw that breaks this camel's back...