You know who I blame for the terrible tone in American politics? Tom Brokaw.

No, not the man himself, but what he represents.

Since Dan Rather famously beclowned himself, Brokaw stands as the last of the respected “voice of God” news anchors (CBS News executive Don Hewitt’s phrase). These were the oracles who simply declared what was news and what wasn’t. Walter Cronkite, the prize of the breed, used to end his newscasts, “And that’s the way it is” – as if he were speaking not just with journalistic but also epistemological and ontological authority.

You can still find this sort of hubris on the masthead of the New York Times, which proclaims “All the news that’s fit to print” – a claim that would be subjected to truth-in-labeling laws were it not for the First Amendment.

Brokaw, an honorable and industrious man, is now playing the role of elder statesman while touting his new book, “The Time of Our Lives.” In it, he writes: “Slashing rhetoric and outrageous characterizations have long been part of the American national political dialogue … but modern means of communications are now so pervasive and penetrating they might as well be part of the air we breathe, and therefore they require tempered remarks from all sides. Otherwise, the air just becomes more and more toxic until it is suffocating.”

There’s much wisdom here. But blaming the new media environment for what ails us is an awfully convenient alibi. It suggests that the old media, of which Brokaw was a master of the universe, played no part in losing the trust of so many Americans.

For starters, when the mainstream media complains about the national “tone,” it almost invariably means the tone to their right. After the tragic Gabrielle Giffords shooting, the mainstream media reported, and liberal pundits raced to insist, that Republican rhetoric – particularly, a pictogram on Sarah Palin’s Facebook page – inspired the suspect. The evidence disproving all of that is voluminous; the record of apologies and retractions from those who reported it is comparably scant.

At the same time, Democratic rhetoric has grown ever more extreme. Vice President Joe Biden said pro-“tea party” Republicans in Congress acted “like terrorists.” House Minority Leader Nancy Pelosi has said Republicans want to “end life as we know it.”

More recently, Biden has insisted that the GOP’s refusal to pass the White House’s jobs bill would cause a surge in rapes, sexual assaults and other crimes across the country. Perhaps he’s right, because the legislation has failed (at the hands of Democrats and Republicans alike), and such offenses at Occupy Wall Street protests have risen (that’s why they’ve built a women-only tent at Zuccotti Park). But you wouldn’t necessarily know that from watching the nightly news.

When tea partiers angrily shouted down their congressmen at some town halls around the country, then-Speaker of the House Pelosi and then-Majority Leader Steny Hoyer wrote in an op-ed article in USA Today that such behavior is “simply un-American.” The mainstream media, which during the George W. Bush years often imagined and certainly trumpeted alleged GOP assaults on the patriotism of Democrats, yawned in response.

Meanwhile, violence, extreme rhetoric and wanton lawlessness have been prevalent in the Occupy Wall Street movement, but the coverage remains largely positive. And any politician who suggests these protests are “simply un-American” risks getting worse than a yawn from the media. The “Today” show even ran a segment on how the protests offered “civics lessons” for children.

All too often it seems like the supposedly evenhanded media cherry-picks positive examples from the left and negative ones from the right. And even when they do cover ideologically inconvenient news, the passion and hysteria are nearly always reserved for the threat from the right.

Brokaw and his heirs don’t understand that such double standards breed precisely the rhetoric they find so toxic. Because the new media Brokaw laments allows conservatives to see how much important news the old media didn’t deem fit to print, they learn not to trust or respect those who wag their fingers rightward about civility – or anything else.

© 2011 Tribune Media Services, Inc.