Ugly and quarrelsome in the best of times, this polarization between the two talk-oriented cable networks has felt even more pronounced this week, as the two gravitate toward diametrically opposed - and racially divided - poles in reaction to the verdict in the George Zimmerman trial.
Al Sharpton, an activist before he joined the network, who has announced plans to orchestrate vigils this weekend pertaining to the case.
On Thursday, Sharpton could be seen all across the network's lineup, repeating portions of an interview he conducted with Martin's parents.
The tone at Fox, meanwhile, has been set by its most prominent hosts, Sean Hannity and Bill O'Reilly, who have dismissed the contention blacks face inequalities within the criminal-justice system. Other lesser lights - such as Eric Bolling - have been even more strident, particularly in regard to defending Florida's permissive gun laws.
MSNBC officials have been criticized in the past for Sharpton's dual pursuits - including his involvement with the Martin case -- and the inherent conflict in the fact he continues functioning as a civil-rights leader while working for the channel.
As for Fox, Hannity's softball interview with Zimmerman essentially provided much of the testimony he declined to give on the witness stand, albeit without having to face anything that resembled cross-examination.
Having committed itself to being "The Place for Politics," MSNBC is awkwardly positioned to pivot into a reporting mode, inasmuch as everything seems filtered through a political prism. CNN is generally the beneficiary during breaking-news events, but has consistently struggled to maintain the audience that tunes in at those moments, which explains current attempts to inject more pizzazz into its presentation.
One of the principal achievements of Fox News under Roger Ailes, by contrast, has been its ability to weave the DNA of a partisan political operation into the framework of a news channel, despite a posture that during key parts of the day more closely resembles talkradio. It's a trick MSNBC hasn't fully mastered.
Conservative antipathy toward the Obama administration has been highly beneficial for Fox, setting the network up as perhaps the most formidable and cohesive voice of the opposition. Yet even with that, Fox's response to the Zimmerman verdict appears to be doubling down on speaking to (and for) an older, predominantly white and conservative-tilted audience.
Some moderate and conservative commentators have suggested such an approach is likely a losing one for the Republican Party because of the nation's shifting demographics. In a recent column about immigration reform, for example, the New York Times' David Brooks wrote "this country is heading toward a multiethnic future. Republicans can either shape that future in a conservative direction or, as I've tried to argue, they can become the receding roar of a white America that is never coming back."
Still, issuing that roar appears to be a perfectly viable formula for Fox, which doesn't need to gain support from 51% of registered voters but merely attract enough viewers to dominate the cable ratings race. And despite cosmetic changes to the network's talent lineup, those marching orders are unlikely to change.
Where does that leave us? As usual, with two so-called news networks that have largely cast aside any pretense objectivity and can't even agree on a set of facts, much less the terms for a constructive debate. And the oddities never seem to end, such as MSNBC's Chris Matthews taking it upon himself to apologize on behalf of "all white people."
In showbiz terms, it's a more colorful way of receiving news -- and one reason CNN has struggled to compete by occupying a middle ground.
When it comes to the rancorous tone, though, watching this white-black divide unfold over the past week has bled into a thoroughly depressing shade of gray.
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