Picture ID is better, for example with a Driver's License. However the US recently enacted a law requiring people entering back into the US to have a Passport. Now, when I inquired about what if we didn't have a passport, the border guy (Canada-US border) said "legally we have to allow a US Citizen in with a birth certificate." So, while perhaps legally a Passport is not required, it isbetter to have one, or you could fact problems getting back into the US. Don't want to be stuck in Mexico, unless you want to be there for a while. Which many people do, and I am not saying it is bad, but most Americans would prefer to be able to get back into the USA.
enough to beat a Mexican
No, you need a valid passport from your country of origin and a travel visa from the country you are entering.
Enough to cross the border.
You have to get documentation that shows your grandfather was an American Indian. Then a copy of your parent's birth certificate showing the grandfather and then a copy of your birth certificate showing the parent should be enough. The link to the Department of Interior, responsible for the Bureau of Indian Affairs, provides further guidance.
You mean those working in the US? Some of them cross back the border on Christmas or Easter. Some others don't, at least until they get enough money to return back to Mexico.
Not enough info. Which border?
yes
As of March 2010, all U.S. citizens must present valid passport documentation. If you're arriving in the U.S. by air, then a passport book is required. If you're arriving by land or sea, another form of passport documentation, such as a passport card or enhanced driver's license, will suffice.
An army strong enough to maintain its border and fear of those on the other side of the border.
Depends on how far up the gulf shore you are. In Texas, it would be miserable in the Houston area, but balmy close to the Mexican border. Pensacola would be chilly, but the keys would be nice and warm.
Well Most likely yes it is
You don't need a passport to fly within the continental US or your birth certificate.