Broken people, after all, can always find some equally broken rationale for the carnage they cause. And the brokenness of 58-year-old Jim Adkisson can hardly be doubted after he walked into a Unitarian Universalist church in Knoxville, Tenn. on Sunday and, according to police, shot eight people, killing two.

He might as well have said he did it because he didn't like the color of the building, a black cat crossed his path or the voices in his head thought it a good idea. Except, he didn't. Police say that, according to the four-page note he left, he went on the rampage because he couldn't find a job and because he hates gay people and liberals.

Even through the brokenness of the man, that reasoning resonates.

From the days the first President Bush branded it "the L word" -- i.e., the ideology that dare not speak its name -- conservative politicians and media figures have been relentlessly effective in selling the idea that "liberal" is the brand name for every wrong thing they see, every opinion they disagree with, every change they fear. They have not been hampered by excessive devotion to nuance.

As in the pundit who claims "liberal" is a mental disorder. And the politician who says liberals are in league with Satan. And the preacher who said Sept. 11 was caused by liberals. And the other preacher who says liberals cause natural disasters.

It has reached the point where I no longer have the faintest idea what liberal -- or, for that matter, conservative -- even means.

Oh, I know what they used to mean. To be conservative was to be suspicious of change and federal oversight, to embrace minimalist government, fiscal responsibility and a strong national defense. To be liberal was to be welcoming of change, suspicious of militarism and committed to activist government that worked to protect and uplift those who are shoved to the margins of American life.

That's what they meant then. What they mean now seems to depend on the needs of a given moment.

Your humble correspondent has never been much for ideology. I find it hard to believe liberals have a monopoly on truth. Same for conservatives. And frankly, as far as I'm concerned, any worldview that can be summed up in a word probably isn't much of a worldview.

But it is increasingly the case that what we are being presented isn't a debate between competing worldviews so much as it is a morality play: righteous good versus unholy evil. Conservatives have cast themselves in the former role, leaving liberals the latter. It's a libel to which liberals have responded as the bug does to the windshield: splat.

Unable to say what they believe or to frame it in any compelling way, they have allowed themselves to be defined instead from without, standing ineffectual in a mudstorm of invective. They are, the propaganda goes, effete, unpatriotic, unstable, un-American, anti-God, evil,and the source of a voter's every problem, down to and including the death of his goldfish and the breakup of his marriage. It is so over the top, so patently ridiculous, it's almost funny. Until you remember that dehumanizing people inevitably has consequences.

That's what Knoxville is, a consequence.

No, conservatives did not cause this bloodbath. Jim Adkisson allegedly did. But in telling him "liberals" were the source of his every disaffection and woe, conservatives certainly validated the hatred and madness that drove him.

It would be a fitting tribute to those who were lost in Knoxville if this tragedy gave the authors of the ongoing morality play cause for pause -- and reflection. Or is accountability yet another lost conservative value?

Leonard Pitts Jr. is a columnist for the Miami Herald. E-mail him at lpitts@herald.com.