As Britain’s general election campaign began, the Conservatives, led by Prime Minister Theresa May, enjoyed a comfortable margin in the polls. On April 21, the Daily Telegraph’s average of polls put the Conservatives at 42.6 per cent. On the other hand, Labour—the official opposition led by Jeremy Corbyn—enjoyed on average just 26.8 per cent favourability. (The Liberal Democrats, the U.K.’s more centrist party, was polling at 10 per cent.) As recently as the middle of this month, after local council election results showed Conservative gains, the thinking held that May was set to win a huge majority—exactly what she said she wanted at the outset.

But as of early this week, that nearly 16-point margin has shrunk to perhaps as little as six points. Even averaged, the Telegraph now puts the difference between the Conservatives and Labour at roughly nine points.

What happened?

A number of theories abound. One involves Theresa May herself, and the drum-tight campaign she has helmed. Since the start, May has been characterized as conducting her hustings as far away as possible from ordinary Britons. Unfortunately for her, efforts to counteract the perception that she is disconnected from average people have instead reinforced it; footage of one run-in with a member of the public featured May being loudly reprimanded for disability benefit cuts. Journalists have also criticized May for avoiding their questions. Again, video aided in that argument. A widely shared clip from a campaign event showed May wondering aloud at a questioner: “You’ve got a pen in your hand, are you a journalist?” (He was.)

That aloofness contributed to the party’s next problem: a policy plan to have elderly people with savings and property valued at more than £100,000 pay for their own old-age care—and, if they were unable to pay, the cost would be deducted from their estate after death. The policy was immediately panned and labeled a “dementia tax”. Labour quickly bought Google ad space under searches for “dementia tax” that linked to an attack page. The Conservatives had bought similar search-related ads, linking to their own explanation. In the end, they merely helped disseminate the negative terminology. The Tories were forced to backtrack on the plan entirely—an unprecedented mid-campaign reversal.

Meanwhile, Labour has defied initial performance expectations in another way. At the outset of the campaign, common opinion held that Corbyn, as divisive a figure within his own party as he had polled nationwide, would lead Labour to its worst seat count since the early 1980s—a result that might have led finally to his ousting as leader. But Corbyn has arguably proved a more successful campaigner than he has been a party leader.

Labour’s left-wing message, including costly platform proposals (which leaked early) to nationalize commuter rail, energy and water supply, and to pour money into the National Health Service, has found some welcoming ears. The party’s acceptance of Brexit, with the hope of striking a fair deal for Britain, has done an end-run around the staunchly anti-Brexit Liberal Democrats. Labour may even be winning the social media war.

Corbyn has also proved to be more telegenic than expected, relatively speaking. However, he still fights both his personal activist past and his party’s record. He has had trouble answering whether he wants Britain to renew its Trident nuclear weapons program, for instance. And Tuesday, he could not answer how much his party’s child-care proposal would cost, prompting the BBC’s Emma Barnett to ask: “Is this not the issue with the Labour party that came up under Gordon Brown, that we cannot trust you with our money?”

But a tightened race is not a finished one. For one thing, as Britons discovered following the 2015 campaign when few predicted the slim Conservative majority, the polls can be wrong. Or misleading, anyway.

When regional vote intention patterns are examined, for instance, the outlook for Labour remains grim, according to data from Martin Baxter of the data site Electoral Calculus. Last week, Baxter and another researcher, Martin Robbins, wrote at the Guardian that, particularly in the north of England, regional polling still suggested a swing to the Tories. Some of that vote swing hinges on former U.K. Independence Party voters who are likely to abandon that party in favour of the Conservatives. According to Baxter, it means even safe Labour seats in northern England could be up for grabs. So, while national polls show an overall lift in the Labour vote, in a riding-to-riding assessment of possible support, that upward trend is either weaker or disappears completely. “For all the excitement, Labour’s polling is still far worse than it was at the last election, when its vote share was over-estimated in predictions,” they wrote.

In other words, the polling may be inflating Labour’s share of the vote. This may be especially true when it comes to young people, who pollsters find support Labour overwhelmingly more than the Tories. When it comes to predicting youth turnout, the polls are at odds. A Survation poll found that a whopping 82 per cent of the 18- to 24-year-olds it reached said they would vote, whereas an ICM/Guardian poll found only 44 per cent would. Depending on which scenario holds true—and where those votes might be distributed—could determine a lot for Labour.

Late Tuesday, a poll from YouGov for The Times showed a potential shock finish: that the Conservatives could fall short of a majority, though The Times noted a caveat via YouGov’s chief executive: “The figures could change dramatically before June 8.” Or not. But if that poll holds true, all these theories about what exactly prompted such a change of heart from the electorate—whether it was policy or personality—may just be noise. Maybe the simplest solution behind Labour’s turnaround is the most familiar, too. Maybe it’s just that Theresa May’s Conservatives are more of the same, and Jeremy Corbyn’s Labour are something different.