Nigeria, Aug. 15 -- I used to be an avid consumer of daily news. I woke up to it and went to sleep with it. For hours each day, I consumed whatever intellectual fare the cable networks had prepared: breaking news, exclusive interviews, heated debates, political panels, and an endless parade of pundits. I watched them all with the reassuring conviction that I was becoming better informed. To some extent, perhaps I was.

I would not suggest that the world of yesterday was some idyllic El Dorado in which everyone agreed and lived happily ever after. It was not. Yet compared with today's deeply polarized and perpetually agitated environment, it can sometimes appear almost tranquil by comparison.

There was a time when America seemed to embody...