Bah Jesus3, the last thing you should be promoting is US isolationism... that is not what the world needs. The US could do a lot of good with its power, the problem is wasting it on stuff like Iraq instead... bad policy does not mean that policies should simply be abolished in that area.
As for the petition... whilst OPEC is obviously a cartel, it kind of rises above standard national antitrust laws, your only realistic option of really tying some actual consequences to the outlawing of OPEC would be military intervention. I do not imagine there are many people who support the action when presented like that, but judging from the 2nd link given by goga that is what the initiative-taker of the petition truly has in mind, as such I feel this petition misrepresents itself to those from whom it requests a signature. I would advise all against signing it for this reason alone.
Well, there is of course another way, one could place an embargo on oil from OPEC member states. However it should be obvious to most though, that the US is far too dependent on oil to do that. Moreover, China, India, Japan and Europe should offer plenty demand for the OPEC to manage, even if Europe tries to shift its dependence to Russia whilst China invests in oil in Africa. The point though, is that the US is far more dependent on OPEC than vice versa (in my estimation) and that economic measures are therefore not viable... thus one arrives back at the aforementioned military measures.
As for the US defending Kuwait and Saudi Arabia... surely noone believes that was an act of benevolence, if so, surely the US would be doing more to tackle and resolve wars in Africa (rather than criticizing the UN, the only institution doing something about it). The US used military intervention to serve its own means, whether or not the results have been satisfactory and self-serving does not change that representing the situation as some sort of moral high ground taken by the US, ingratefully scoffed by those helped in the process is just wrong.
P.S. Should the spammer read this thread once more (doubtful) here's a essage for him, aimed especially at the 2nd link: Down with Israel! ;-)
"We must face the fact that the preservation of individual freedom is incompatible with a full satisfaction of our views of distributive justice."