Britain's parliament votes Tuesday on the withdrawal agreement that Prime Minister Theresa May's government negotiated with the European Union.
May canceled a previous vote in December when it was clear she did not have enough votes for the deal to pass, and since then little seems to have changed.
Both pro- and anti-Brexit lawmakers oppose the terms of the agreement. May sought to garner last-minute support Monday by asking them to examine it again while warning of the consequences if the deal fails.
The biggest point of contention has been the arrangement to have an open border between Northern Ireland and EU member Ireland that would keep Britain in some way tied to EU trade policies until the two sides can negotiate a new trade deal.
EU leaders said Monday the so-called "backstop" arrangement would only be in place as long as necessary.
Negotiators from Britain and the European Union agreed to the terms of the Brexit deal in November after difficult talks, and if the British parliament votes against the agreement there is great uncertainty about what will happen next.
May would have until next Monday to put forth a new proposal. There is also the chance Britain could reach its March 29 withdrawal deadline with no terms in place to specify just how it will relate to the European Union when it is no longer a member.
Some lawmakers have proposed holding a second referendum like the one in 2016 that set Britain on the path toward leaving the EU. Others want parliament to take control of the Brexit process from May and her Cabinet.