Yes, now you must have a passport to leave or enter the US.
As long as you have a valid passport/Nexus card and haven't committed a crime or done anything else to cause you to be denied entry you should be allowed to reenter Canada.
No, if such citizen keeps his/her passport at hand.
Yes no matter what the distance you will need a passport to travel across the border.
If you are a US citizen and have the identification for it then Yes you can if you are to travel by land and sea. If by air, you need your passport.
Just the passport and you're good to go.
To get accross the border to travel to Seattle from Canada, a passport would be needed. Traveling via plane to Arizona would also require a passport, since the person traveling is a Canadian citizen.
When you are not a citizen of the USA a passport is usually required to enter the US. However, for many years citizens of the USA, Canada and several other western hemisphere countries did not need a passport to enter the US. Because of increased security procedures, even US citizens must have a passport or passport card to reenter the US across the US-Canada land border or by sea from the Caribbean after 18 May 2009. Passports have been needed for all entrants by air for a year before that.
Not yet. But things will change in the spring of 2009.
starting in 2008, YES we need passports to get into Canada
If you are a US citizen you will never be denied the enter to your country. However, you will need to show a valid passport in order to cross immediately If you don't possess a valid passport, you will be asked to step aside to prove your citizenship, which is a process that might take 10 mins or 2 hours depending on the situation. If you are crossing the border recurrently without a passport you might be subject to fines.
what documents does a us citizen need to reenter us after visiting canada? -answer- This depends on the border crossing. For the most part you need to show that you are a US Citizen. Usually, just a drivers liscense and vehicle registration with a car that has US plates and you not talking with a 'canadian' accent. If you are not the typical 'easy to identify' American, but naturalized or something, then you need a copy of your naturalization papers or some other documentation like a passport or something to show you are allowed legally in this country. So, it may be easy to leave the US without the correct documentation, but its harder to get back in without it.
They can't. Irrespective of ancestry or race, if you are a US citizen, you are entitled to enter the United States without passport, provided you can show proof of citizenship, including IDs and birth certificates.