Jonathan Haidt is quite correct that a healthy society benefits by having about equal input from both the liberal and the conservative forms of thinking, because they complement each other perfectly. One is strong in all the areas where the other is weak, and vice versa. The liberal mentality is actually the "mothering" force in a society, whereas the conservative mentality is the "fathering" force. Each one is required, and an effective marriage of the two produces the best society.

Take the case of prewar Japan, where you had an intensely conservative, rigid, authoritative society...pretty much totally under the stern "father" mentality. They idolized patriotism, discipline, honor, sacrifice for the group identity, rules, duty, militarism, and extreme authority at every level. That's almost exclusively the energy of the father principle, with the mother not even making an appearance. It led them to utter disaster, because it was too extreme and too one-sided.

I think in prewar France, on the other hand, you had a strikingly liberal society...one which unconsciously, subliminally was manifesting primary the "mother" principle so typical in liberalism....flexibility, individuality, many shades of gray, subtlety, a multiplicity of opinions and views rather than a single doctrine....and that is an approach which also becomes fatally flawed when it is too dominant. It set the French up for defeat and collapse in 1940.

You see, if all the people in a boat move to one side of the boat and perch there on the rail, it's quite likely to tip over in rough waters!

Thus a society is healthiest when its liberal and conservative forces are engaged in approximately equal measure. When they can unite in common purpose, then that society is at its absolute peak of capability.