Mark Kleiman may have the best take so far on the question of whether left-leaning types want America to lose in Iraq:
I noted earlier that Eugene Volokh's attempt to find important American liberals who support the Iraqi insurgency had yielded a result within measurement error of nothing whatever. But Henry Farrell's search for right-wingers who falsely assert the opposite -- who claim that large segments of the American left support our enemies -- has been much more productive.
The conclusion is inescapable: Large segments of the American right are making demonstrably false charges of disloyalty, thus weakening national unity in wartime. How unpatriotic of them!