I would expect a populist party the most likely to form. Immigration would be a big issue to it. I imagine one could run on these planks:
~ Cut of bureaucracy in government, remove tax cuts on rich, cut corporate welfare, and lower taxes on poor and middle class
~ Heavily fight illegal immigration and also slow legal immigration slightly.
~ Punish Corporations that are exporting jobs, lower small buisness taxes
~ Invest in and strongly push for renewable energy use
~ States' Rights on most social issues
~ Cut the defecit
I think you captured a good description of a very real potential third party (although I don't think 'renewable energy' will be a big issue).
This is pretty much the description of the potential Perot voters in the late spring of 1992 (before he first pulled out).
I estimate it encompasses (now) about a quarter of the electorate willing to abandon the Democrats and Republicans.
