Requirements for a passport depend on where and how you're planning to travel. If you plan to travel from the United States by air and you are a US citizen, you will need a passport to gain re-entry to this country (and to enter a different country).
If you're planning to travel by ship, for example on a cruise, or by by land (car, train, truck, bike) you can visit the Caribbean, Mexico and Canada with a certified copy of a birth certificate and a government-issued photo ID or a passport -- (but if your cruise departs from Vancouver or St. Martin and you must fly to get to the ship, you'll need a passport). The exact date passports will be required for travel by ship have not been established, but it should be in the fall 2008.
The above applies to US Citizens; alien residents have different rules depending on the status of their Permanent Residency and their country of citizenship.
Now Canadians and Americans need passports when visiting each other.
Not even Ow.
No, but check with your airline.
foreign affears
Yes.
No, passports are for traveling to other countries.
They are US nationals meaning they can hold a US passport; but they are not US citizens which means there are certain limitations for them (e.g. taking high positio federal level jobs or vote in presidential elections)
I do not know where you are but any international flights require passports.
Not if you are a US citizen flying directly to and from Puerto Rico.
Yes, babies need passports to travel to Canada.
Yes, babies need passports to travel to Mexico.
Yes, children need passports to travel to Canada.