(CNN) On Monday night, the British Parliament handed Prime Minister Theresa May her latest setback in the country's attempt to respect the voters' wishes and separate from the European Union -- seizing control of the timeline of Brexit in a stunning move that hadn't happened in more than a century.

It can feel to an observer across the ocean -- like, well, me -- all very confusing, as May seems to have lost her political momentum (and then kind of, sort of, regained it) 100 times in the course of the Brexit process.

So is this the beginning of the end for May? Or the end of the end? And what does it all mean for the extrication of Britain from the EU? I reached out to my old friend Sebastian Payne , now the Whitehall correspondent at the Financial Times, for clarity. Our conversation, conducted via email and lightly edited for flow, is below.

Cillizza: How unexpected (or not) was the Parliament vote to take control of Brexit decision-making out of May's hands?

Payne: Not at all. MPs have been threatening for months to wrestle control of Brexit from May's dying government -- given that she has chalked up two historic defeats over her deal. It's a huge moment in Westminster with the rule book for Parliament torn up.

On Wednesday, MPs will control the business in the House of Commons for the first time in 140 years. There is no accountability for their actions and it sets a huge, some say, precedent. When MPs don't like what the government is doing, they can have a vote and just take control. Even supporters of remaining in the EU are nervous at what it means.

This is what happens when you don't have a written constitution. Like the best and worst of Britain, we're making it up as we go along.

Cillizza: Can she possibly remain in office now? (I feel like I ask this question every time we talk.)

Payne: I know, I know. Conservative MPs tried to remove May at the end of last year but failed to get the numbers. So thanks to the party's rules, she can't be challenged again until December. But the cabinet is rapidly losing patience; one minister says she has gone "haywire."

Everyone from party grandees to the chief whip has told May this week she's going to have to announce a timetable for leaving Downing Street. As we're reporting in the FT, the party's big donors are turning off the taps until she goes. But as one No.10 adviser told me, "Her fingers are Super Glued to the desk." She has dreamed of becoming prime minister since she was 16, she's not going to give it up easily. But every day, everyone I speak to says she will be gone in months.

Cillizza: Hasn't Parliament taken May's problem and just turned it into their problem? Or is there a clear way forward on Brexit favored by Parliament?

Payne: Kinda. The problem is that May set red lines for the negotiations that restricted what kind of Brexit deal she could broker. She refused to keep the UK close to the EU's single market and customs union, which naturally points towards a hard exit with the bloc.

Parliament takes a different view; many MPs would like to stick close to the EU even though the UK is officially leaving. Over the next few days, MPs will use their new powers to vote on different kinds of Brexit and we'll see if there's a majority for another form. My money is on keeping a customs union: That means the UK will have more control of its laws, borders and money, plus protect its manufacturing supply chains -- but crucially can't sign new trade deals. Most Brits really don't care, but a lot of Brexit-supporters in the Conservative Party do. Cue more outrage and cries of betrayal.

Cillizza: Is it now more likely or less likely that the Brexit deadline is met, given that the deadline is now April 12? Why?

Payne: The EU has given the UK one firm extension: April 12, but it has some caveats. If May manages to pass her deal -- or any deal -- by the end of this week, then the EU will allow until May 22 to get it all into law. But the EU27 leaders are fed up with May and Britain generally. They aren't going to keep granting extensions while our political process works itself out. So regardless of whether MPs want to leave then or not, the EU has decided that is the case. It is no longer up to Westminster.

Cillizza: Finish this sentence: "In two weeks, the big headline on the Brexit negotiations will be _________." Now, explain.

Payne: "MPs back softer Brexit, May refuses to accept."

Parliament is probably going to show there is a clear majority for a different form of Brexit than May's, but the prime minister will refuse to accept it (she has ruled out every other deal). So Britain's executive will be staring down its legislature, while the EU helpfully says it can reconfigure the deal to suit the will of MPs. We'll be back into stalemate.

If May doesn't blink and MPs don't blink, then we're still heading for a very chaotic crash exit on April 12. Or even -- eep -- a general election. Which neither party will win and we'll be back into deadlock.

It really is the most almighty mess.