There have been conservatives and liberals ever since Og the caveman went out to meet the new guys who came over the hill while Gog barricaded himself in the cave and sharpened extra flints.
A healthy society needs both. Be realistic, conservatives: we have benefited a lot from "outsiders," including the French. Be realistic, liberals: sometimes we DO need to guard the hearth and home against invaders. A balance of people who are skeptical of strangers and people who are friendly to them keeps a society open to allies and still able to defend itself.
There are pathological extremes in both groups. At the pathological extreme of the conservative mindset, enemies are everywhere -- and if you are afraid of everything, you can't effectively protect yourself against anything. You dissipate your energies shooting at every shadow.
At the pathological extreme of the liberal mindset are those who argue that if we just go out to meet Genghis Khan with open arms and picnic baskets, we can win him over as a friend. They also think that anybody who says we should arm ourselves against him should be locked up for their own good.
When we characterize either group by its pathological minority, we are robbing ourselves of the strengths of the majority. Conservatives and liberals need each other. Conservatives do not need pathological conservatives any more than liberals need pathological liberals.

