JEREMY CORBYN’S raucous online supporters have a simple mantra whenever a new poll appears: “It will go higher.” Dismissed as magical thinking when it began in the spring, it has turned into one of 2017’s more accurate political predictions. Labour’s polling almost doubled, from 25% of voters when the election was called in April to 45% in one recent survey. Magical thinking trumped political expertise.

Yet the growth has stalled. On December 3rd a poll by Survation put Labour eight points clear of the Conservatives, who stood on 37. But this was an outlier. Other polls give Labour only a slim lead or put the party level with the Tories. A flurry of governmental scandals and cock-ups, ranging from ministerial resignations to rocky Brexit negotiations, has failed to put a dent in the Conservatives’ polling numbers. Why isn’t Labour doing better?

Start with Brexit. Labour’s position on the topic—that it would seek to “retain the benefits” of both the single market and the customs union—is either cynically slippery or simply confused. Either way, it means the party has found it hard to hammer the government’s handling of the negotiations. This leaves British politics in a curious stalemate, with an opposition ducking the chance to pummel the government on the biggest issue of the day.

Others point to tried and tested metrics to explain Labour’s political plateau. Labour still lags behind the Tories in voters’ perception of economic competence, notes Ben Page of Ipsos-MORI, a polling company. Philip Hammond is seen as a more capable chancellor than John McDonnell, his opposite number. Although Theresa May’s approval rating has collapsed, Mr Corbyn still sits (just) behind her when people are asked who they would prefer as leader, according to YouGov, another pollster. And Mr Corbyn is still less popular than his party. Labour MPs in marginals across the Midlands wince when asked whether he is an asset. One cabinet minister has a blunt explanation for what is keeping the Tories’ polling numbers afloat: “Fear of Corbyn.”

Supporters of Mr Corbyn offer a simple retort to those questioning why Labour is not farther ahead: pundits were wrong about the election in June and they are wrong again now. Pollsters underestimated Labour in the run-up to the vote and it is feasible that they are making the same mistake, concedes Mr Page. After all, the job has not got any easier. Polling companies are left “literally guessing” when it comes to predicting who will turn out to vote, according to one executive. This is especially problematic given Labour’s commanding lead among young people, whose voting track-record is erratic.

But whereas voting intention is tricky to measure, other metrics are clearer—and they are moving against the Tories. Earlier this year, Mrs May enjoyed a 39-point lead over Mr Corbyn on the question of who would be the better prime minister. Now “Not sure” outranks them both. The Tories’ lead on economic confidence has also fallen by half, from 18 points to nine, according to Ipsos-MORI. The fear among some Conservative advisers is that the party has mimicked Wile E. Coyote: it has already run off the cliff, but not yet plunged. Brexit is protracted and complicated. Although voters are concerned about it, they “have completely tuned out” says Lord Cooper, who runs Populus, another pollster. How they will react when they wake from their stupor remains to be seen.

Barring a collapse of the government, the next election is not scheduled until 2022. “We have to wait for an event that focuses people’s minds on politics for there to be a big shift either way,” says one Labour adviser. Until then, British politics is stuck in a holding pattern. A final run-off between magical thinking and political expertise has to wait.