We plan to travel to the US next year to visit family, and my kids have both US and Swiss passports. The US ones have expired, however, and it is hassle to get them renewed. Can they simply use their Swiss ones for entry into the US? I know they say that you must use your US passport if you have one, but how would they know? Anyone have any experience doing this at US immigration at the airport?

Depends on the mood of the dude checking you at immigration, because you are technically not allowed to travel to and from the US on another passport if you are a US citizen. I've heard anecdotes on both sides: some friends have gotten stopped and questioned and not allowed to leave the airport without a multi-hour hassle (although they all eventually got in), some went through with a slapped wrist and a "bring your US one next time."

My guess is they know from some sort of "sophisticated" names database, but everyone I know who is a dual citizen has been asked something to that effect at immigration. My brother gets stopped all the time (three passports) and US immigration definitely knows about the other two.

I would try making the whole family come in on Swiss ones because some with US and some with Swiss would be a red flag.

Travelling on Swiss passport will prompt the visa-waiver process. You then have to register on the ESTA system with all the associated customs checks and fee as well. Presumably there are cross checks, and questions like when you last visited US, etc. Seems quite easy they could connect the dots. You are definitely taking chances in this day and age I think.

Also, make sure you have the new swisspassports that work with the visa waiver program, or otherwise you would also have to get new swiss passports.

You'll find these notices on the USA government sites:

Traveling with a U.S. Passport - U.S. citizens, including dual nationals, must use a U.S. passport to enter and leave the United States.

source: http://answers.usa.gov/system/selfse...=en&COUNTRY=US

Most U.S. citizens, including dual nationals, must use a U.S. passport to enter and leave the United States.

source: http://travel.state.gov/travel/cis_p.../cis_1753.html

Also, you don't have to go all the way to Bern to renew the passport - there's a consulate in Zurich that can also handle passport renewals, though it is of course smaller and with fewer opening hours. They are pretty responsive by email for appointments http://bern.usembassy.gov/service.html

If you want my advice, get your passports renewed, entering the USA as a European citizen can be a hassle. Also they will most likely have you in their computers and it's going to get complicated.

Anyway, a Swiss national needs

- an ESTA clearance
- a new biometrical passport or a machine readable passport (Model "03") issued before 10/26/2006
- no record of arrests or criminal prosecution

to participate in the visa waiver program and enter the great USA

Did it three times this year ;-)
Tom