Carnivore conservation has a great story on the slow and threatened return of the jaguar to the American Southwest.
If the border fence is built, I think part of the plan should be a reintroduction of jaguar.
Note that President Bush recently signed an authoization to build a 700 mile fence along the Arizona/Mexico border, but authorizations require appropriations. These are often not forthcoming, and the whole thing might be an election year stunt. In the next Congress conservationists should lobby for jaguar money.