THIS is a heady time to be a wonk in Washington, DC. Seldom have the political classes had so many facts at their disposal. Campaigners cite blizzards of statistics and reams of research, much of it produced by powerful new digital tools. Yet national debates have rarely been so sourly unproductive.

This is odd. Each month sees the launch of a data-driven news outlet, offering to explain the world with bullet points, pie charts and nifty interactive graphics. Competition is fierce between such online outfits as Vox.com (run by Ezra Klein, formerly of the Washington Post) and fivethirtyeight.com (the brainchild of Nate Silver, the Dumbledore of the in-data-we-trust school of political analysis). Then there are spin-offs run by print publications, such as “The Upshot”, a new, graph-laden website from the New York Times. The hot book of the moment in policy circles, “Capital” by Thomas Piketty, a French economist, is full of tables buttressing his views on inequality (see article), and directs readers to a stand-alone website, a trove of previously unseen data. The internet has bestowed cult status on wonkish members of Congress who bring big graphs and charts to debates. Screenshots of the best are preserved on floorcharts.com, a blog run by a Capitol Hill TV producer with tens of thousands of followers. (The Economist has been known to turn its own charts into wonky videos.)

Alas, there is a gap between the high-minded empiricism all around, and the nasty tone of political debate. Poisonous distrust is part of the puzzle: each faction distrusts the other’s methodologies. Every other day another Twitter-squall breaks out, as partisans or pundits denounce some new opinion poll or study, harrumphing about skewed samples and other flaws.

Until recently a common understanding of reality drove cross-party policymaking. A Republican president, Richard Nixon, created the Environmental Protection Agency with bipartisan support. A Democrat, Bill Clinton, worked with Republicans in Congress to reform welfare, and came close to a deal to preserve the long-term sustainability of Social Security. Such comity is growing harder to find. Right and left do not just disagree on how to regulate pollution; most Republican voters do not accept that man-made global warming is happening. As for America’s future solvency, leading Democrats, such as Senator Elizabeth Warren of Massachusetts, question whether Social Security faces a crisis at all, suggesting that its benefits should in fact be expanded.

What is going on? Democrats have an explanation. The whole country is polarised, they say, but the right has moved further from the centre. What’s more—say Democrats—too many Republicans live in a bubble of para-facts and propaganda, fed to them by Fox News or sham studies paid for by conservative billionaires. That is a bit too glib. For one thing, the left has its own shibboleths of irrationality. Just ask about genetically modified crops, declared safe by the scientific establishment, but reviled as Frankenfoods by the Subarus-and-sandals set. For another thing, most Americans don’t watch Fox News (or much news at all).

Lexington, himself a data-fan, has a different theory, offered with regret. Perhaps politics is flooded with more data than voters want or can usefully process? Some of those vowing to “explain” the world empirically are sincere: their reverence for data betrays a certain despair among moderates, as they try to construct a canon of basic facts whose meaning right and left may constructively debate. Other data-lovers are partisans in disguise, engaging in an arms race with foes: you sow doubt about global warming with glacier measurements, here are 100 years of sea temperatures to end debate. You say welfare is out of control, my numbers show the worst inequality since the Robber Barons.

Each slab of fresh research is a new way of waging old cultural wars. March saw boffin-on-boffin combat in a federal court, as rival scholars argued whether children raised by gay parents thrive or suffer. Mark Regnerus, a sociologist, told of grim outcomes after studying hundreds of adults with gay parents. Critics, including the American Sociological Association, retorted that he had mostly studied children of opposite-sex couples who reported a parent having a same-sex affair, meaning that his work—commissioned by conservative groups for use in legal battles—said much more about unstable families than gay parenting.

In 2013 the Heritage Foundation, a conservative outfit, triggered a data-commotion by estimating that a pathway to citizenship for all 11m illegal migrants now in America would cost the government a net $6.3 trillion in lifetime benefits and services. The whole premise of the study is wrong, complained Senator Marco Rubio of Florida, a pro-reform Republican: it assumes that migrants, even once legalised, will not better themselves.

If I hate you, your facts are wrong

In the face of such a torrent of data, voters may be forgiven for tuning out. Instead they look at each faction and decide if they trust its motives. Climate-change sceptics look at environmental types, and think they see the same hair-shirted scolds who 30 years ago wanted to ban big cars because oil was running out. Democrats hear conservatives citing deficits as a reason to cut food stamps, and think: new panic, same-old heartlessness. The hipsters reading Mr Piketty in a Brooklyn café may not have studied his historical data-sets, but they love seeing a clever man advocating a wealth tax. Tribal instincts nearly always trump the careful weighing of facts, especially when partisans stress that experts disagree among themselves.

Washington’s passion for data does not signal the start of a new Socratic age, in which the political classes jointly search for truth. In today’s politics everything is a weapon with which to club the opposition. Why should facts be different?