"Civil society" does not mean people acting politely. It is a specific term for the network of relationships that people form which are based in churches, non-profits, and other community organizations. Civil society has long been recognized by experts as the foundation of functioning democracy.
Take a look. Once upon a time ago the typical American shared PTA membership, volunteer work, and perhaps a church pew with those of opposing political points of view. Now civil society itself is on the rocks, and what's left of the networks of the left and right in the US are nearly severed from each other. A liberal's network might weave through the DFA and the the local Unitarian (or UCC, or Quaker, or etc.) church; a typical member of the radical right networks almost exclusively through megachurches where virtually every one of their interests can find a home (not accidentally, I suspect).
There are radical differences in values between the left and right. The left has strong social values. The right has made a virtue of selfishness. Someone on the left who did nothing to aid others when it was within his or her power to do so, or who betrayed the trust of family and friends to fulfill their whims (for example, by having an affair) is thought poorly of. The right believes that aiding those in need only encourages bad behavior, while acts of betrayal to further one's indulgences don't count, in their eyes, among the Saved (who are of course hopeless sinners who have been arbitrarily selected by Jesus for unearned, undeserved, salvation, so how could one expect anything other than sinful behavior among His Elect?). Hell, the left and right can't even agree on simple facts.
In virtually every category recognized by experts as critical to functional democracy, we come up frighteningly short.
And again, why do you believe Americans can act in their own best interest while the Lebanese and residents of the Balkans -- literate modern peoples all-- could not? There's absolutely no evidence that any human is largely informed and rational, and mounds of evidence that humanity is irrational and, in most complex situations, ignorant of key pieces of information necessary for rational decision making. Last I checked, Americans are human.