The men are so near to each other in all their convictions and theories of life that nothing is left to them but personal competition for the doing of the thing that is to be done. It is the same in religion. The apostle of Christianity and the infidel can meet without a chance of a quarrel; but it is never safe to bring together two men who differ about a saint or a surplice.

– Anthony Trollope, “Phineas Redux”

During the 1990s, I always found the East Coast-West Coast hip-hop rivalry interesting. Biggie and Tupac, no doubt, had more in common with each other than either of them did with, say, Garth Brooks.

So why did they focus their hatred on each other?

There’s something about internecine squabbles that really brings out the bitterness. Police officers, I’m told, don’t like domestic disputes. They see them as some of the most dangerous situations they confront.

Turf battles are ugly — which explains why a candidate like Michele Bachmann would attack a conservative like Rick Perry — while rarely criticizing a moderate like Mitt Romney.

Interestingly, this same principle holds true in the punditry world. And today, two of my friends provide two good examples.

As you may have heard, Erick Erickson is departing CNN. On his RedState blog today, he writes that, “For three years I have received unmitigated hate and loathing from the left and, ironically, from a lot of folks on the right.”

“For some reason saying something negative about the GOP was fine here at RedState,” Erickson added, “but saying the same damn thing on CNN brought in a flurry of emails from conservatives accusing me of selling out. Funny how that works.”

Meanwhile, Kirsten Powers, a liberal who appears on Fox News, endured some vicious attacks on twitter after she criticized President Obama for slighting her network. This prompted her to tweet:

Why do “liberals” so consistently attack the way I look and make sexist comments when they disagree with my columns?Serious question.

— kirsten powers (@kirstenpowers10) January 29, 2013

I’d love to tell Kirsten it’s because liberals are meaner than conservatives, but my guess is it has more to do with the fact that other liberals get mad when one of their own goes on a conservative network and criticizes their leader.

So what’s the lesson? — that Erickson had better toe the conservative line on CNN — and Powers had better toe the liberal line on Fox — or … they are sellouts?

In the past, I’ve compared this to gang warfare — or prison. In the yard, you’d better have somebody watching your back. You’d better have a team. You never tell anyone outside the family what you’re thinking.

When pundits break this code — when they think for themselves — there’s a price to pay.