Brussels, Belgium (CNN) What can the UK achieve in three weeks that it couldn't in three years?

The most obvious answer to this is, worryingly for some, not very much.

While the European Union offered Prime Minister Theresa May -- and her vision for Brexit -- a final lifeline this week , it did so with caveats and, crucially, harder deadlines than before.

It's these deadlines that European leaders hope will focus the minds of British lawmakers as they return to the House of Commons to try and find a way out of the Brexit deadlock.

About last night...

The UK essentially now has three options, and each comes with increasingly urgent logic.

Option one: Approve the Withdrawal Agreement . The UK will then leave the EU on May 22 and enter the transition period. More on that later.

If MPs vote the deal down, then they have a decision to make by April 11: stand in the EU parliamentary elections or don't.

Option two: Don't stand in the elections, held between May 23-26, and leave the EU before then. It is unlikely that any substantial new deal could be struck by this point. What the EU would do at this point is unclear.

Option three: Stand in the elections and request a long extension. This makes softer Brexit all but inevitable and undoing Brexit a lot more likely.

Meaningful Vote Three

At some point next week, May will bring her Withdrawal Agreement back to the Commons. She needs to flip 75 MPs if she's to win by a margin of one. Given she dedicated some of this week to accusing them of betraying the nation, it's hard to see them feeling charitable. All the PM can hope for is that the EU has bought a new level of focus to London.

Why should MPs who hate the deal back it suddenly? There are arguments to be made either way. Ultimately, all the Withdrawal Agreement does is place the UK into a transition period, allowing for future negotiations about where all this ends up. If your biggest fear is remaining in the EU, then this is the case for holding your nose.

Taking back control

If May fails, as is widely expected, then it's likely that MPs will do everything in their power to take control of Brexit away from the PM.

On Monday, MPs will vote on an amendable motion. This means that the Commons votes on a question put forward by the government, which MPs can amend to suit their needs.

It is highly likely that an amendment will be made demanding that the PM allows the Commons to hold a series of indicative votes so MPs can finally say what they are for, not just what they are against.

And if parliament *actually* says what it wants?

You had to ask, didn't you? It's very likely that any consensus that could be reached across the Commons would be a softer Brexit than the one May is currently pursuing.

That, I am afraid, is still a fairly open-ended answer. It might mean the need to renegotiate, which would mean a longer extension, which would mean being in the EU elections, which could mean a second referendum, ultimately.

The key point here is that cross-party consensus might sound nice, but on an issue as divisive as Brexit, it's as likely as anything to blow up both main parties.

While things are far from rosy and three weeks is not enough time to sort much, it's worth noting that while Brexit might not be going terribly well, the last three years have been a huge learning curve for the entire UK. We know more now than we did.

So while the next bit of the Brexit process might look crunchy, the decisions made in the coming days will not be made lightly.