Actually, he HAS declared war on the United States. He’s said publicly that he doesn’t want the US to win the war on terror because then America and capitalism would be strong, and he has said that America and capitalism are the 2 great evils that he - as God, he says - has to get rid of.
So yes, the guy who says he owns the democratic party has publicly declared war on the United States of America.
And in September of 2008 he showed the world that he meant it, and has the allies to make good on his threats.
I know of no democrat who has renounced him or his war on America.