(economist.com) ALL political campaigns involve a certain amount of looking voters straight in the eye and lying to them. But America’s mid-term election campaign has involved more flim-flam than most. The Republicans, if you believe Democratic attack ads, oppose equal pay for women, want to ban contraception and just love it when big corporations ship American jobs overseas. The Democrats, according to Republicans, have stood idly by as Islamic State terrorists—possibly carrying Ebola—prepare to cross the southern border. And they, too, are delighted to see American jobs shipped overseas.

Only a blinkered partisan would believe any of these charges. Alas, partisans are far more likely than anyone else to vote, especially in elections like this one, where the presidency is not up for grabs.

A survey by the Pew Research Centre finds that 73% of “consistently conservative” Americans are likely to cast a ballot on November 4th, along with 58% of consistent liberals. Among those with “mixed” views, however, only 25% are likely to bother. That, in a nutshell, is why both parties are pandering to the extremes. Their strategy relies less on wooing swing voters than on firing up their own side to get out and vote. Often, this involves telling them scare stories about the other lot. The same Pew poll finds that dislike of the other party is one of the strongest incentives to vote. Republicans with a “very unfavourable” view of Democrats are far more likely to turn out, as are Democrats who loathe Republicans. With Barack Obama in the White House Republicans are angrier than Democrats, and that is one reason why they are expected to win (see article). Most polls say they will capture the Senate and hold onto the House of Representatives.

America’s cycle of polarisation and alienation is self-reinforcing. As the debate grows shriller, moderates tune out. Politicians come to rely more and more on the votes of die-hard partisans, so they say and do more extreme things, alienating yet more moderates. Most members of Congress are more frightened of being tossed out by their own party’s primary voters—typically for the heresy of compromise—than they are of losing an election to the other party.

America’s electoral system needs reform. It is too late to change the rules before this election, however, so it is up to moderates to walk to a polling booth and be counted. To those who grumble that there is no point voting because they don’t like any of the candidates, we offer two counter-arguments.

Read more here: America’s mid-term elections: The silent centre; If moderates don’t vote Tuesday, extremists will thrive