The Whitehouse petitions are silly. The most they’ve ever done was to get a non-committal highly-sanitized political response from some unnamed Whitehouse officer.
And breaking away from the UN would possibly be the worst move ever. It will leave Israel completely vulnerable to Lebanese terrorists should the UN decide to pull out its peacekeeping forces.
Also, what you are proposing is the Libertarian approach. That the US should not get involved in foreign policy at all. This is a wonderful ideal if it weren’t for the fact that it also means cutting off aid to Israel and Egypt (whose American aid is one of the major factors in not attacking Israel).