Reality," Stephen Colbert once famously said, "has a well-known liberal bias."

It was one of those jokes that isn't, one of those barbs that captures something painfully true, allows you to see it with clarity you never could if viewing straight on. It's worth noting that Colbert said this years before that jump-the-shark moment last week when conservatives accused the Labor Department of conspiring against them. In case you missed it, it happened when the government released figures showing the unemployment rate has tumbled to 7.8 percent.

Most of us considered this good news. Because it validates President Obama's narrative of a slowly improving economy, many conservatives did not. They called the figure a fraud -- "monkey business," in the words of Donald Trump. Former GE CEO Jack Welch saw it as evidence of malfeasance from "these Chicago guys." Fox "News" asked, "Is the number real?"

And so it goes in the conservative War on Reality.

Not that this was the first salvo in said war. Just before the numbers came out, conservatives were working to discredit polls that showed President Obama leading Mitt Romney. "Bogus," said Rush Limbaugh.

You see, the war goes back a ways. Back to Sen. Jon Kyl saying that 90 percent of Planned Parenthood's activities are abortion-related and, when called on that lie, issuing a statement that what he said was "not intended to be ... factual." Back to Sarah Palin sounding the alarm about death panels, back to Glenn Beck saying conservatives started the Civil Rights Movement, back to people pretending there is some mystery over the president's birthplace.

Heck, it goes back to the Bush administration cutting inconvenient facts from government reports, back to Bush brushing aside a pessimistic report on Iraq by saying the intelligence community was "just guessing."

The point here -- this cannot be overemphasized -- is not ideology. Rather, it is about the fact that we cannot effectively debate ideology if we do not have a body of facts in common.

Under such circumstances, political discourse must devolve into incoherence. We cannot discuss what color to paint the room if we cannot agree on what constitutes red or green -- or the room. We literally have no shared language with which to even have the discussion.

This is the legacy of the War on Reality. Some of us live under a new ethos, fueled and abetted by Fox, the Internet and talk radio, which holds that facts are optional and reality, multiple choice -- and that anyone who questions this is part of the conspiracy against you. The results have not been pretty. When, in the history of American political discourse, have conservatives -- some, not all -- seemed more paranoid, put-upon and ready to believe themselves the victims of outlandish plots?

Hillary Clinton was rightly derided for saying a "vast right-wing conspiracy" was out to get her husband. But if that one-time utterance made her sound ridiculous, what shall we make of this constant drumbeat from the political right? What shall we make of a mindset in which the answer to every criticism, the response to every unwelcome fact, is to point to a conspiracy of bias that exists mostly in their minds?

Now, we reach a sobering watershed. Who knew even the professional numbers crunchers in the Labor Department were part of this vast left-wing conspiracy?

Hearing that, one must believe one of two things: either math also has a liberal bias, or, it is time to ask ourselves what becomes of a country where problem-solving is paralyzed because problem solvers cannot agree on a common reality?

Math, should it need saying, has no liberal bias. So give that question some hard thought.

After all, we have only the one country. We may not share the same reality, but we will certainly share the same fate.

Leonard Pitts is a columnist

for the Miami Herald.

lpitts@miamiherald.com