Confused about Brexit? Even seasoned observers have struggled to sort it out.

British Prime Minister Theresa May is trying one more time to get parliamentary support for the withdrawal deal she negotiated with EU representatives. Photo / AP

If you're confused about Brexit, you certainly aren't alone. Britain's path toward leaving the European Union is complicated and confounding - full of forks, U-turns and more than a few dead ends. Even seasoned Brexit watchers have at times struggled to figure out what's going on.

British Prime Minister Theresa May is trying one more time to get parliamentary support for the withdrawal deal she negotiated with EU representatives. For it to pass, she would need to convince at least 75 lawmakers who voted against it - twice - to change their minds. If she can't get the math to work, Britain risks the economic earthquake of a no-deal withdrawal.

But to understand how the Brits got here and what's at stake, we need to back up a bit.

Q: What is Brexit?

A: May has said, "Brexit means Brexit." But what that means is that Britain plans to leave the EU, gaining the ability to control its borders and make its own trade deals - or, as some people see at it, losing the automatic free-movement and free-trade rights that come with membership.

Q: Why is Britain leaving the EU?

A: Basically, because Brits voted for it, 52 to 48 per cent, in a referendum on June 23, 2016. Concerns about immigration and sovereignty were the top reasons people voted to leave.

Q: Who voted for Brexit?

A: England and Wales voted to leave, while Scotland and Northern Ireland wanted to remain. London was strongly against. The vote divided both main political parties: Conservatives and Labour. Labour leader Jeremy Corbyn voted to remain, though he is lukewarm on the EU and has regularly criticised it as a capitalist club. May, a Conservative, also voted to remain - though she asserts, repeatedly, that she is committed to delivering on the referendum result. The most notable Brexiteers are Boris Johnson, May's former foreign secretary, and Jacob Rees-Mogg, another Conservative.

Q: So when does Brexit happen?

A: The original departure date was supposed to be March 29. But the British Parliament hasn't yet agreed on how to leave. It has twice rejected May's withdrawal plan by historic margins. Last week, EU leaders granted a short extension. If British lawmakers finally approve May's deal this week, they can leave the EU on May 22. If they reject it, they must plan an alternative by April 12 or leave without any transition provisions or protections that evening.

An effigy of British Prime Minister Theresa May is wheeled through Trafalgar Square during a Peoples Vote anti-Brexit march in London. Photo / AP

Q: Why does Parliament need to approve Brexit, after there was already a referendum?

A: The referendum wasn't legally binding, and it only asked people whether they wanted in or out of the EU - not how they should leave. Because Britain is a parliamentary democracy, meaning Parliament is sovereign, it was agreed after a lengthy legal debate that Parliament would get a "meaningful vote" on the deal - a decision that significantly complicated May's negotiations.

Q: What's in her withdrawal deal?

A: The 585-page deal lays out things such as a timetable for a transition period, what happens to EU nationals living in Britain and the amount of money Britain has to pay the EU. It doesn't get into anything about trade deals or other aspects of the future relationship between Britain and the EU. That's saved for a whole separate set of negotiations, to the chagrin of all those with Brexit fatigue.

Q: Why don't people like May's deal?

A: Hardcore Brexiteers think she has made too many concessions to Europe. They want a more decisive split. Those who are more pro-Europe argue that the deal risks economic damage to Britain without sufficient benefits.

Q: What's the issue with the Irish border?

A: An open border on the island of Ireland has helped to resolve decades of conflict - allowing "unionists" in Northern Ireland to feel securely part of the United Kingdom while "republicans" in the north can feel connected to the Republic of Ireland in the south. But that open border has been possible only because the EU's customs union and single market avoid the need for border checks. Once Northern Ireland leaves the EU, along with the rest of the United Kingdom, there will have to be a different way to preserve an open border and maintain peace. That's where the backstop comes in.

Demonstrators carry posters and flags during a Peoples Vote anti-Brexit march in London. Photo / AP

Q: What's the backstop?

A: It's an insurance policy to guarantee an open border between Ireland and Northern Ireland. Until a future trade deal somehow dispenses with the need for border checks, or until technology is developed that does the job of border agents and achieves an invisible border, the backstop would require the United Kingdom to remain in the EU customs union and parts of the single market. That's controversial in part because the UK would be subject to EU rules even after losing its say over them.

Q: Could Brexit be stopped?

A: Theoretically, yes. The EU's highest court ruled last year that Britain could unilaterally reverse its decision to leave. A petition to cancel Brexit has garnered more than 5 million signatures, becoming the most popular petition ever hosted on Parliament's website. Those numbers should trigger a parliamentary debate and a government response. But many lawmakers would be wary of supporting a complete reversal, and, anyway, they're several steps away from that happening.

Q: Couldn't Britain just hold a second referendum?

A: Since the Brexit vote in 2016, the prospect of a second referendum has gone from something barely imaginable to something remotely possible. The idea has considerable public support. About a million people demonstrated in London in favor of a "people's vote" on Saturday. But critics argue that a second referendum would be deeply damaging to democracy and a betrayal of those who chose to leave. It could also unleash further political chaos.

Q: Have people changed their minds on Brexit?

A: Certainly some have. But many people feel even more strongly now about the stance they took and have begun to define themselves as leavers or remainers. Polls suggest that a slight majority of Brits would now opt to remain in the EU, but that swing is partly the result of changing demographics. Younger people are overwhelmingly pro-remain, and teens who couldn't vote in 2016 are now of voting age. Meanwhile, the majority of voters 65 and older voted to leave - and some of them have since died.

Q: What's the worst-case scenario for Brexit?

A: Most economists would say a "no-deal Brexit," a scenario in which Britain leaves without an agreement with the EU and without the two-year transition period that comes with it. Most likely, Britain would revert to World Trade Organisation trade rules at its borders. But the sudden break could cause major disruptions to trade and travel. The International Monetary Fund projected that up to 8 per cent of Britain's gross domestic product could be lost. Britain and other EU countries have put together elaborate and costly contingency plans. Brits have also been hoarding toilet paper and chocolate just in case. A no-deal departure is definitely possible. One study that came out last year estimated that there were five possible scenarios for Brexit, and all but one resulted in no deal.