IT IS common for one of Britain’s great parties to be in crisis while the other is in clover. Labour tore itself apart in the Thatcher era and the Tories did the same during the Blair years. But Britain is currently witnessing something unusual: both its main parties are in crisis at the same time, divided over their future direction, racked by factional fights and worried about leadership challenges.

The Conservative Party’s civil war over Brexit is intensifying as B-day approaches. Twenty pro-Brexit MPs have declared that they will vote against Theresa May’s Chequers deal, easily enough to derail it. Backbenchers have started to come up with alternatives. Nick Boles, who has allies in the cabinet, has produced a blueprint for a two-stage solution: remaining in the European Economic Area for a few years while negotiating a trade deal.

The Tories’ position is complicated by the fact that Boris Johnson is conducting a leadership bid under cover of “chucking Chequers”. Mr Johnson frequently uses his column in the Daily Telegraph to denounce the government of which he was recently a part. He is also working with Sir Lynton Crosby, who ran Mrs May’s election campaign in 2017, to fire up grassroots support across the country. Mrs May has hit back by saying that Mr Johnson has “no new ideas” and doesn’t offer “serious leadership”, a verdict that a startling number of Tory MPs would endorse.

Labour, meanwhile, has spent the summer consumed by a civil war over anti-Semitism, which has grown molten hot since a video emerged of Mr Corbyn telling a group of Palestinians that “Zionists” didn’t understand “English irony” despite having lived in the country all their lives. Labour’s most recent prime ministers, Gordon Brown and Tony Blair, have described anti-Semitism as a stain on the party. Frank Field, a veteran MP, has resigned the Labour whip and some 15 others are reportedly thinking of doing the same. The problem of anti-Semitism is closely linked to a broader problem of thuggery. The Corbyn surge has brought in troglodytes who have dwelt in dark basements for the past few decades, consumed by righteous hatred not just of Tories but also of Blairites and other traitors.

On September 4th the party’s National Executive Committee (NEC) tried to cool the row by accepting the International Holocaust Remembrance Alliance’s definition of anti-Semitism in full. But this was small comfort for the party’s embattled moderates. Corbynites won all nine places in an election to the NEC, with one going to Peter Willsman, who has blamed Jewish “Trump fanatics” for stirring up the anti-Semitism debate. Mr Corbyn’s allies are preparing to use their control of the party’s machinery to launch their ultimate weapon: the power to deselect MPs who don’t agree with them.

The two major parties are incompetent as well as divided. Their leaders, a charisma-free robot and a superannuated Marxist, are two of the most unimpressive in recent history. The cabinet and shadow cabinet are stuffed with hangers-on. Chris Grayling made a thorough hash of things as justice secretary, only to be put in charge of transport, where he has made an even bigger mess. Leslie Rowse, a historian of Elizabethan England, argued that the basic rule of academic life was that second-raters would always appoint third-raters over first-raters. Rowse’s rule now applies to politics on both sides of the parliamentary aisle.

The result is a negative equilibrium. The government can get away with being useless because it faces a useless opposition, and vice versa. The political system is designed to hold regular tests of strength, as government ministers explain their policies to Parliament. But these tests of strength have turned into tests of weakness, as incompetent opposition spokesmen fail to hold incompetent ministers to account. It is notable that the only serious blow against a minister in recent months was struck by a backbencher, Yvette Cooper, who dispatched Amber Rudd, then home secretary, during a committee meeting.

Tipping the balance

Economic theory would suggest that there is an easy way to break out of the equilibrium: raise your game and the voters will reward you. Competent Labour or Conservative politicians could dump their leaders or, failing that, form a new centrist party. But this happy outcome looks unlikely. The Tories and Labour are too gripped by ideological battles to focus on competence. The Conservative Party is so delicately balanced over Brexit that it would rather keep Mrs May (and by extension Mr Grayling et al) than risk splitting. Labour is so deeply embroiled in an ideological war over Corbynism—a war the Corbynites are winning—that it has no time for questions of mere competence.

The British system makes it difficult for a new party to get off the ground. The last time this happened, with the formation of the centre-left Social Democratic Party in 1981, the new outfit won enough votes to shore up Thatcher, but not enough to win significant representation in Parliament. The existing centrist party, the Liberal Democrats, could fill the gap created by the big parties’ failures. But it is hard for a third party to break through even when it has a dynamic young leader and 50 MPs. The Liberal Democrats are stuck with a 76-year-old leader, Sir Vince Cable, and a dozen MPs. The latest Survation poll puts them at 6%, a point behind the UK Independence Party. Sir Vince’s position is so desperate that he is talking about changing the party’s rules so that he can be succeeded by somebody who isn’t an MP, a recipe for disaster in a parliamentary system.

No wonder a growing number of Britons are beginning to worry that Britain could end up leaving the European Union without a plan or a parachute. And no wonder people are losing faith in the country’s ability to produce competent politicians and sensible policies. The problem with negative equilibriums is that they are much harder to get out of than they are to get into.