Curious Word: equipoise

Prof. Ulhmann, who spent time in the Ford era Justice Department and the Reagan Administration, is a trove of good words. The prof is the source of this one...

1. A state of being equally balanced; equilibrium; -- as of moral, political, or social interests or forces.
2. Counterbalance.

Instead of my usual obnoxious example, I yield to Edmund Burke.

I cannot see how the unequal representation which is given to masses on account of wealth becomes the means of preserving the equipoise and the tranquillity of the commonwealth.
-- Edmund Burke, "Reflections on The Revolution In France"

Of course, though I'm off again on again reading that particular work, I didn't discover it on my own. The example came from here. Shame on me.