Well, they could be imitating, say, Teddy Kennedy's style.
I was recently reminded that all of William Shakespeare’s early education was conducted in Latin. WFB, I’m sure, had such a vast vocabulary because of his intellect, but also because of his immersion in Latin through his Catholic school upbringing. Rigor in a foreign language, even a “dead” one, enriches one’s native tongue. Buckley epitomized this phenomena.