I've been thinking that the security function served by a passport is very rapidly becoming obsolete (or at least redundant) for travel to most countries in the world. It could be replaced by a plastic photo ID card -- which you could then call a "passport" I suppose. And with strong biometrics, it could be replaced by nothing.<p>Let me explain this with typical cases where a passport is used:<p>(1) You're entering your home country with your passport. Pretty much at every secure border crossing, they're going to use your passport number to pull up absolutely every bit of info that appears in your passport, including your photo, plus a lot more info from the home country's computers. The passport serves at most as a "something you have" security token. They already have your photo, so the only case where the physical passport helps is avoiding impersonation by someone closely resembling you.<p>(2) You're traveling to a foreign country that needs a visa. In that case, you will have submitted a ton of information, including your photo, to the foreign country in advance to get the visa. When you arrive at the foreign country, it's just like case (1) above.<p>(3) You're traveling to a foreign country that doesn't need a visa from citizens of your home country. In this case, the proof you need is that you are a citizen of that country. It is likely that the two countries have exchanged a mass of information to make the visa-free travel possible, or they can share the info about visitors in real time as they arrive.<p>It's really the edge cases that the physical passport helps. Like obscure border crossings where they don't have an electronic feed, or very third-world countries, or as a recognizable document to show to hotels/banks/airlines within a foreign country.<p>By the way, I'm not saying that this is a good development. In fact, it's a terrible loss of privacy and furthering of worldwide surveillance. But it seems to be the trend, like the elimination of cash.