I may regret replying having only read the excerpt Eric posted, but I actually like Badiou's "unity pipe."
Calls for unity in the Obama, Kumbya, Live Aid sense should be challenged because they're depoliticizing and hokey. But that's obviously not what Badiou is advocating.
As I read it, to "reverse the dominant idea of the world united by objects and signs, to make a unity in terms of living, acting beings, here and now" entails seeing one's fellow human beings not as abstract bundles of rights, but as -- first and foremost -- fellow laboring animals who eat, fuck, shit, and die just like you do; who have the same immediate, concrete needs (food, clothing, shelter, health care, education) that you do.
This is a pretty radical gesture, because if recognizing everyone else as a fellow human animal is one's starting axiom, then other loyalties (e.g. to one's nation and, by extension, its laws) necessarily disappear.
The Sanctuary movement comes at this from a religious angle, but I think it's essentially the same thing. http://www.usatoday.com/news/religion/2007-07-08-sanctuary_N.htm Roughly speaking, I think Badiou's point is that if more people were doing stuff like this, we'd be in better shape.
-WD