At the root of the dispute is an effort by the Texans to use the North American Free Trade Agreement in order to force the Mexican government to police the drawing of water from the overtaxed Rio Grande River.
The Texan farmers accuse Mexico of violating a 1944 treaty with the U.S.–a pact which divvied up the water in the river which flows for hundreds of miles along the border between Texas and Mexico.
However, that 1944 treaty–in common with many international agreements–didn't provide individuals or groups with the right to sue governments in case of alleged violations of the treaty.
Only with NAFTA, which came into force some 50 years later, did individuals acquire more latitude to drag a sovereign government before an international tribunal.
And in 2005, a bloc of Texan farmers and ranchers mounted a suit under NAFTA, accusing Mexico of harming their livelihoods.
The Mexican government retorted that the NAFTA permits such lawsuits only when there are cross-border investments put in harm's way. If the Texans had set up agricultural operations in Mexico, then they could sue Mexico for allegedly harming those investments through its water-use policies. However, Mexico insisted that NAFTA's legal protections couldn't be invoked by Americans farmers who operated solely within their own borders.
Ultimately, a trio of arbitrators agreed with Mexico, dismissing the case on jurisdictional grounds this past summer.
More:
http://www.embassymag.ca/html/index.php?display=story&full_path=/2007/november/14/farmerssuemexico/
[Proofreader’s note: this article was edited for spelling and typos on November 21, 2007]
Note: http://www.embassymag.c...

If you assume that the United States owns the world (as it "obviously" does), that makes perfect sense. :p
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"George Bush has declared the war on terrorism to be the cause of his generation. The cause of Canadian sovereignty will be ours." - John Godfrey, MP for Don Va
It's been found that (for instance), there is no spare water in any of the Great Lakes. All of it (except for a few inches of surface water) is needed to maintain the hydrological balance of the region.
So what do you have in mind? Say! Maybe I was too hasty. We shoud make a deal to sell off Saskatchewan River water to the US. But we'd have to make sure we get the money up front, because that river system is glacier fed, and the glaciers are disappearing!
I await your learned response..............
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"When you change the way you look at things, the things you look at change."
-Max Planck