Federal vehicle stops near the Canadian border aimed at catching terrorists haven't caught a single Mohamed Atta, but they are catching lots of dopers :

Security stops of cars in rural New England near the US border with Canada, which became more frequent after the Sept. 11, 2001 terrorist attacks, have yet to snare a single terrorist -- but they have contributed to a huge, unexpected increase in marijuana seizures, according to homeland security authorities.

The seizures, which soared from 419 pounds in 2000 to more than 3,000 pounds last year, have pleased the federal Department of Homeland Security but have angered Vermonters and civil libertarians, who say the more aggressive US Border Patrol checkpoints should not be used for everyday law enforcement.

Some Vermonters are complaining about the patrol's more aggressive tactics, especially the use of highway checkpoints as far as 100 miles from the border. They say the random checkpoints -- which stop all passing cars inside the state, even if they're not headed to or from the border -- can make driving within their state feel like being in Eastern Europe under communism.

One problem is that there's some considerable constitutional ambiguity here. The Supreme Court okayed roadblock sobriety checkpoints in the early 1990s under the dubious reasoning that though they do probably violate the Fourth Amendment, any constitutional concerns are trumped by the alarming number of "alcohol-related" traffic fatalities. The hyped-up, inflated number the Court cited at the time was around 25,000. It's now at about 17,000. But when you count only people killed by legally intoxicated drivers, as the L.A. Times did in a terrific 2002 report, the number is closer to 5,000.

Believe it or not, several years later in Indianapolis v. Edmond the Court actually ruled that random roadblocks were not constitutional when used to check motorists for possession of illicit drugs. The reasoning there was that a motorist's mere possession of illicit drugs has little bearing on highway safety, and thus doesn't justify the Fourth Amendment violation (interestingly, Clarence Thomas wrote a dissent in that case in which he called out the questionable distinction between drug possession and intoxication, and held open the possibility of revisiting the legality of DWI checkpoints).

To further complicate matters, the Court ruled 30 years ago that roadblocks are constitutional when they're set up near the border, and used to enforce immigration laws.

I expect we'll see more on this when someone challenges seat-belt checkpoints.

The question, then, is what happens when roadblocks are set up and operated under a justification that's constitutional (border control), but it's clear that they're being used almost exclusively in a way that's unconstitutional (drug searches). That seems to be what's happening in Vermont. Of course, most DWI checkpoints today do more to generate revenue than to actually catch inebriated motorists.

There's also the question of whether 100 miles qualifies as "near" the border.