01/10/2011 03:55 pm ET | Updated May 25, 2011

A Crossroads in Tucson

America has wandered into a broken wilderness and we find ourselves at the lip of a precipice. If we hew to the path we're on, we will certainly tumble into it.

The shooting of Rep. Gabrielle Giffords in Tucson was a terrible thing for our nation, and not just because of the grotesque body count. We have been meandering towards something like this for years, lost in a masquerade that we've come to regard as political debate. And we've ignored, or denied, that the winds we've been sowing could ever rupture the civil peace.

No longer. However this turns out -- if we all turn away from hysterical rhetoric and begin seriously addressing our problems, or cast off our anchor and drift into the uncharted sea before us -- this weekend's events will probably be understood as an American turning point.

It's easy, in a pass like this, for writers to put their minds on automatic and either pray for peace, or call out the militia. It's even easier to cast blame. And it's made yet easier by the growing rumblings found on the comments pages on every political site on the Web, especially -- and I say this with regret -- on right wing sites. On the comments pages of sites like Red State, for instance, posters are beginning to call the shooter a "pot-head liberal".

As it happens, this is the exact opposite of what the right should be saying; the more they insist it's not their fault, find ways to blame their enemies for the shooting, and display their mean-spirited inclinations, the more they cut themselves off at the knees by reminding people of how their rhetoric and tactics helped bring this about. And by denying the obvious, they only encourage attacks from the left--sending matters entirely in the wrong direction.

But in some ways, you can't blame them. Certainly, their reaction is predictable, because the Right has obviously been set back on its collective heels by the shooting; it calls into question their entire narrative--that the republic is in such grave danger that to save it, the ends justify the means.

After all, if the result of that claim is assassination, their claim on legitimacy is called into question. So it's no surprise that most right wingers feel the need to defend their politics with the usual tools--mainly, bullying attacks insisting right-wing innocence, or justification because of the imagined equivalence of left-wing behavior.

But the left is helping. And as anyone who's been reading me on these pages knows, I'm as guilty as anyone.

Just a few hours after the shooting, I found myself telling a clerk at my usual grocery store that the right was going to have a hard time from now on denying that most recent terrorism in this country came from its precincts. A customer immediately insisted the left was just as guilty, dragging Bill Ayres into it. Imagine my surprise when things turned nasty.

But there's no doubt I started it, so let's not rush to blame the guy for launching a brisk exchange of slogans. If I'd been more on my toes, I would have pointed out that his manner was a good illustration of what I was talking about, issued a call for civility, and steered for hypocrisy -- a useful posture in times like that. Instead, I said he was a waste of time, and left.

That gnawed at me for some time, but even worse would have been saying nothing. If America doesn't realize it's coming to -- or is at -- a point of no return, we'll never turn away from it. Even after Virginia seceded from the Union, people were holding out hopes that the North would let the South go in peace. As you'll recall, it didn't work out that way.

In a pass like this, wisdom would mean the right backing off the hysterical rhetoric, and dropping the idea that the republic is in such imminent danger that saving it justifies any means. And the left would allow them to do it without much comment.

But whether that's a realistic option is, at best, a matter of speculation.

Truth is, both sides are spoiling for a fight. The main disappointment with President Obama among liberals, for instance, is that he seeks consensus, when what they want is to get some of their own back, and maybe break some bones. And it's a short step from believing the republic is in danger, and asking the question, "What're you going to do about it?"

But this isn't taking us anyplace we want to be. The fact is, the political wings in this country are already past the point of looking for common ground, and it was just a matter of time before somebody took that short step.

So the question now is whether we can recognize we're at the lip of a chasm, and, just as important, whether we'll step back.

But there's no doubt in my mind that we're near that lip, and that if we tumble in, there's no turning back. Luckily -- and as usual -- history provides us with examples of where current political weather can lead.

For instance, ancient Athens was more or less in the same place at the end of the Fifth Century BC -- just before the Peloponnesian War destroyed it: This is how Thucydides described it:

Words had to change their ordinary meaning and to take that which was now given them. Reckless audacity came to be considered the courage of a loyal ally; prudent hesitation, specious cowardice; moderation was held to be a cloak for unmanliness; ability to see all sides of a question, inaptness to act on any....The advocate of extreme measures was always trustworthy; his opponent a man to be suspected. To succeed in a plot was to have a shrewd head, to divine a plot a still shrewder; but to try to provide against having to do either was to break up your party and to be afraid of your adversaries.

Sound familiar?