First, never treat a liberal as having alpha status in any venue. The Liberal should always be relegated to beta, gamma or delta status.
Second, never approach a Liberal using logic and reason. Liberals respond to emotions and feelings only. In fact science has proved that 98% of Liberal brain activity takes place in the brain stem, the upper brain being largely decoration.
If possible Spector should withhold food, sex or scotch from the Liberal. Sometimes this works.
Finally Spector should not address the Liberal directly and verbally, but rather communicate through his bearing, his mien, his posture, his tone of voice. The Liberal will understand these visual cues better.
Now I must admit I abhor the old bromide that "you can't teach an old Liberal new tricks." I believe all Liberals can learn, at least on a rudimentary level. In Kennedy's case though the bromide may be true.
I know what of I speak. I am, after all, The Liberal Whisperer.