I can't understand why we are not all over this. Venezuela is one of our leading suppliers of oil and is therefore in our national interest. As for justification, this fits squarely (but not literally as some on FR believe is required) with the intent of the Monroe Doctrine.
I remember a comical thread about how two Miami based DJ's got through on a prank call to Chavez a few months back. They played snippets of Castro and Chavez thought he was really talking to Castro himself. It took a while for him realize that it was a joke. Not only is he not the sharpest tool in the shed, but his security is obviously lacking also. One covert operation team should be able to take him out.
Sparta, this would also be the perfect opportunity for the hypothetical mercenary outfit we were discussing (sorry I din't get back to you earlier-holiday). If they made arrangements with the opposition to take out Chavez for 10% of the oil revenue for a year (both sides would likely jump on the offer) Chavez would be taking a dirt nap in the very near future.