In any democratic political system, the parties are supposed to disagree. They’re supposed to fight and argue, denounce their rivals’ ideas, and make the case to voters that they know what they’re talking about while their opponents are fools. In any democratic political system, the parties are supposed to disagree. They’re supposed to fight and argue, denounce their rivals’ ideas, and make the case to voters that they know what they’re talking about while their opponents are fools.

But what’s often exasperating about American politics is the degree to which partisans live in alternate realities. It’s one thing to disagree on the merits of ideas; it’s something else to disagree on whether objective, quantifiable truths are real.

The Washington Post’s Greg Sargent yesterday flagged a fascinating result from the latest Bloomberg Politics poll

Republicans say by 53-38 that the unemployment rate today is worse than when Obama took office. Americans overall say the opposite by 56-34. In January of 2009, the unemployment rate was 7.8 percent, according to the Bureau of Labor Statistics. The rate rose to around 10 percent by October of 2009, then declined steadily to 5.0 percent last month.

Whether or not the unemployment rate has improved is not a matter of opinion. No matter how one sees the world, a 7.8% rate is higher than a 5% rate . That’s equally true for Democrats and Republicans.

But most Republican voters don’t believe it. The “reality gap” persists, and it’s a problem.

Here, for example, is the unemployment rate since President Obama took office.

If GOP voters want to make the case that Obama’s policies don’t deserve credit, fine. If they want to argue that there are other, more important metrics, no problem. If they want to suggest the rate would have fallen faster with a right-wing economic agenda, we can at least have the conversation.

But the polling suggests Republicans prefer to pretend reality isn’t true. It’s as if a form of cognitive dissonance is kicking in: the president is bad, falling unemployment is good, ergo unemployment must be higher, not lower.

This is by no means limited to unemployment. President Obama increased border security, and Republicans are absolutely certain that he’s done the opposite. The deficit has dropped by $1 trillion in the Obama era, and Republicans just know in their gut that the deficit has ballooned.

The Affordable Care Act has lowered the uninsured rate to unprecedented depths, but Republicans are confident that “Obamacare” hasn’t improved the uninsured rate at all. The United States’ international reputation has improved dramatically since the end of the Bush/Cheney era, though Republicans believe it’s deteriorated.

Maybe the bubble of conservative media has shielded many Republican voters from details the party’s voters don’t want to hear. Maybe Republican voters have a tribal reflex that gets in the way.

Whatever the cause, this “reality gap” makes conversations awfully difficult.

Q: If the unemployment rate has fallen quickly under Obama, why should we dramatically change economic course in 2016?

REPUBLICAN VOTER: Because the unemployment rate has gone up, just like the deficit.

Q: But reality says–

REPUBLICAN VOTER: Spare me your economic mumbo-jumbo.