Last week Fox News, without advance warning, parted ways with Tucker Carlson. Carlson was host of their flagship 8 p.m. program, which had a viewership larger than that of all the other cable news networks’ offerings combined. He had over three million viewers. Just as importantly, he had by far the highest ratings among the 25 to 49 - year - old age group (the demographic used by advertisers to determine how much they were willing to pay for their ads). Two days after Tucker was forced out, his time slot’s audience had been reduced by 56 percent. Chris Hayes ...