I have to believe that's in the noise. It's for some very specific purposes and, as I recall, when I looked it up at one point for no particular reason, it was fairly burdensome to do.

Perhaps, but the passport cards aren't at all difficult or rare; you can apply for both in the same form.

> 21,995,760 (includes 3,361,037 passport cards)

https://travel.state.gov/content/travel/en/passports/need-pa...

Fair enough. I forgot that you could apply to get both (which basically gives you a spare federal photo ID which is also good for entering Canada or Mexico). I have a Global Entry card so I didn't bother.

Not sure what the other stats are counting as passports and if they're double-counting or not.

You can also get two passport books--basically for visiting countries that may do visa stamps and which won't admit people with the "wrong" visa stamp--which is what I was talking about.

I think a bigger reason for having multi US passports is how much of a black hole sending your passport to a foreign embassy for a visa can take.

A common problem for those that do training/sales around the world for short trips.

Sometimes quite amazing how long an embassy can take when it’s one of the country’s big industries you’re heading to to train them on the expensive thing they surely want to maintain…

Although I'm not sure the degree to which getting multiple passports plays into this. Maybe it's easier to get multiple passports these days.

Pre-pandemic, I canceled a couple of trips to India for visa issues--wouldn't get back in time for other trips--although my understanding is the situation has improved.

Passport cards are now more readily available since state DMVs can process them as part of the RealID initiative. They're cheaper than a proper passport but I would venture many passport holders have one for convenience.

Some of the purposes I remember were:

- When needing a passport while the other passport was in visa processing

- When needing to travel to a country A that denies entry based on having a passport stamp from country B. Like Azerbaijan/Armenia and Israel/Some Arab countries.

For many years I had two US passports; my civilian Blue and my official Maroon. Not quite the same as that link, but there are reasons.

For a while my family of four had seven passports, though three of those would be counted for Japan.

A bit of googling suggests you can have 3 or 4, but I can’t find a US government source on that.

Wouldn't be surprising. Up to two normal passport books, an additional passport card, and a special issuance one (diplomatic, military). Can't use the special ones for personal travel so you'd need both forms.