Politicians across the spectrum believe voters are vastly more rightwing than they are, even after elections prove otherwise

The current US government shutdown isn't the first time a small group of hard-right politicians has held the rest of the country to ransom, and it presumably won't be the last. (I'm not sure it's widely appreciated exactly how small that small group is, in the present case: we're talking 30 people here. That's like letting The Polyphonic Spree determine America's future!)

And if it always seems to happen this way – with the whole political system gravitationally sliding off to the right, not the left. A recent paper suggests why: American politicians, whether they're liberal or conservative themselves, chronically misperceive the voters who elect them as more conservative than they are.

Before last November's nationwide elections, David Broockman and Christopher Skovron, political scientists at the Universities of California and Michigan, asked almost 2,000 state-level political candidates about their voters' views. How did people in their district feel about same-sex marriage being legal, or whether the country needs universal healthcare? What were their views on abolishing federal welfare programs?

"Pick an American state legislator at random," Broockman and Skovron report in a new summary at the Scholars Strategy Network, "and chances are that he or she will have massive misperceptions about district views on big-ticket items, typically missing the mark by 15 percentage points."

The mismatch is most extreme among conservative politicians, who typically overestimate their voters' conservatism so much – by 20 points, on average – that they're essentially claiming their district is more conservative than the most conservative district in America. Most of those conservatives are sure their voters agree with them on same-sex marriage and healthcare – but in three-fifths of cases, they're wrong.

Oh, and these out-of-touch politicians don't learn from experience, either: when Broockman and Skovron posed the same questions after the 2012 elections, once it was obvious what voters actually thought, they found the basic discrepancy unchanged.

Which makes it a bit easier to understand how even the upper echelons of Mitt Romney's campaign could have been caught so unawares by his defeat. (It also suggests a "simple lobbying strategy" for progressive groups, the authors write: "Just let legislators know the truth about what their constituents think and want!")

The explanation for all this isn't necessarily cryptic, and Broockman and Skovron hint at what's probably at the root of it: conservatism talks louder, because conservatism talks with more money, because people with plenty of money tend to prefer conservative policies.

What's striking, though, is the suggestion that politicians aren't following the money in a purely cynical fashion, ignoring voters in favour of a few big donors: if these findings are to be believed, they really, truly imagine their voters share their views. Perhaps that's the most alarming thing about the Tea Party faction directing events in DC at the moment – not just that they're out of step with voters, but that they sincerely believe they aren't.

[Hat tip: Michael Tomasky.]