Initial Report: (read all the way through before you react as there is some interesting information further down)
Apparently the Department of Homeland Security has a policy that their jurisdiction extends to 100 miles within a national border. According to the ACLU this means that there is a strip of land running completely around the continental US where your 4th Amendment rights against unreasonable search and seizure (or at least the requirement that there be probable cause and a warrant) are completely abrogated. The ACLU also estimates that about 2/3 of all Americans live in this 4th Amendment free zone (they call it a Constitutional Free Zone, but since the rest of the Constitution still appears to be in effect, this might be a bit of hyperbole).
Darlene Storm of computerworld.com's blog wrote an article about it yesterday, which my cousin GTG forwarded on to me. It's quite disturbing but some things aren't clear.
1) According to the quotes in the article, DHS claims that they have a right to conduct warrantless searches of all possession, including computers, at border crossings.
2) DHS claims to have border authority 100 miles from the border and throughout several states including Connecticut, Delaware, Florida, Hawaii, Maine, Massachusetts, Michigan, New Hampshire, New Jersey or Rhode Island. It is not clear if this is a separate claim of authority like the ACLU states or if it just happens that there is no area of each of the those states further than 100 miles from the coastline. Looking at the map, it appears the latter so I would assume that DHS is not making an additional territorial claim.
3) It is also not clear whether DHS is claiming a stop and search outside of border crossings. I know that they can stop and question you but I don't know what authority they have to search. The ACLU appears to be claiming that they have an unlimited right of stop and search in that zone, but living in a border town I have never seen it exercised. They have frequently stopped to ask people who look suspicious a few questions(my parents, for example, have parked and walked across the border to visit me and were stopped and briefly questioned) but whether DHS has the authority to stop and search is unclear from the article, the ACLU's claim notwithstanding. Nothing in the DHS quotes suggests that they are claiming this right.
I would be interested in knowing more. I would like to know if DHS claims that they have a legal right to stop and search anyone in that zone, do they claim that this right extends to my home, my car, or just my person if I am walking? Have they searched people within this zone other than those crossing the border and if so, were those people under suspicion of illegally crossing?
Update: I am posting this article because this is floating around. I think it is worthwhile to know the facts about this claim by the ACLU.
It would appear that this is substantially overblown. Doing a little more research I found a Supreme Court case from 1973 that states that they can't search people without probable cause within that 100 mile zone, so apparently this is not a new issue. The rules for border agents other than at a border crossing or entrance are pretty much like any law enforcement. They can stop you on reasonable suspicion that your car contains illegal aliens, they can search you if you consent or if they have probable cause, and they have to have a warrant to search your home, just like any other agency.