After two years of negotiating, cajoling, infighting, bitter splits and resignations, an embattled Theresa May finally puts her unloved Withdrawal Agreement to the House of Commons later today.
She spent yesterday making a last-gasp appeal for support, warning MPs that it would be the 'height of recklessness' to reject her plan when no alternative deal was on offer.
The prime minister had hoped a letter from EU leaders Donald Tusk and Jean-Claude Juncker would help to reassure those worried that the backstop - designed to prevent a hard Irish border - could become permanent.
The letter says that if the backstop came into force, it is intended to apply only temporarily.
However, there was little sign yesterday that the letter has had the desired effect.
DUP deputy leader Nigel Dodds was dismissive, saying it provided no 'legally binding assurances'.
But the prime minister was insistent that rejecting the backstop altogether would mean a no deal.
As matters stand, the British government is facing defeat on the Withdrawal Agreement with some predicting Mrs May could lose by as many as 100 votes.
The outcome remains to be seen but if the deal fails then we will be plunged into even further uncertainty.
A no confidence motion by Labour leader Jeremy Corbyn seems unlikely to succeed but Mrs May's survival will be in doubt.
A no deal Brexit would be disastrous in a number of respects but it is clear extreme Brexiteers are prepared to risk economic chaos in their desire to leave the EU at all costs.
The widely-held view that Mrs May's plan would be highly advantageous to Northern Ireland is cutting little ice with the DUP and others in Westminster.
If this agreement is rejected then the government needs to come up with a Plan B that ensures we do not crash out of the EU on March 29.
