British lawmakers were preparing to deliver their verdict on Prime Minister Theresa May's divorce deal with the European Union on Tuesday after more than two years of political upheaval.
All signs point to it receiving a resounding thumbs-down from Parliament, a development that would throw British politics further into turmoil, just 10 weeks before Britain is due to leave the EU on March 29.
Despite a last-ditch plea from May for legislators to give the deal "a second look," it faces deep opposition, primarily because of measures designed to prevent the reintroduction of border controls between the UK's Northern Ireland and EU member Ireland.
Pro-Brexit lawmakers say the deal will leave Britain bound indefinitely to EU rules, while pro-EU politicians favor an even closer economic relationship with the bloc.
That leaves the agreement facing likely defeat on a day that could bring a very British mix of high drama, low insults and convoluted parliamentary procedure.
Environment Secretary Michael Gove urged colleagues not to let their visions of a perfect Brexit get in the way of what he said was a good deal.
"The real danger is if people do not vote for the government this evening, we face either a no-deal Brexit, with the short-term economic damage that would bring, or worse: no Brexit at all," Gove told the BBC.
Lawmakers are scheduled to vote Tuesday evening, after the last of five days of debate on the deal struck between May's government and the EU in November. May postponed a vote on the deal in December to avoid a resounding defeat, and there are few signs sentiment has changed significantly since then.
Reassurances from EU leaders that the Irish border "backstop" is intended as a temporary measure of last resort have failed to win over many skeptics. And the EU is adamant that it will not renegotiate the 585-page withdrawal agreement.
In a sign of the widespread opposition, Parliament's unelected upper chamber, the House of Lords, voted by 321 to 152 late Monday in favor of a motion saying May's deal would damage Britain's economic prosperity, internal security and global influence, while also rejecting the idea of leaving the EU without a deal.
The Lords' vote has no direct effect on the fate of May's deal. May says rejecting the agreement would lead either to a reversal of Brexit overturning voters' decision in a 2016 referendum or to Britain leaving the bloc without a deal, a course she said would damage the country's economy, security and unity.
Former education minister Nicky Morgan, who said she planned to vote for May's agreement, warned that the U.K. wasn't ready for the economic upheaval of a no-deal Brexit.
"There are millions of people in this country watching Westminster and Parliament very anxiously today," she told the BBC.
If Parliament votes down the deal, May has until the following Monday to come up with a new proposal. So far, May has refused publicly to speculate on a possible "Plan B."
The main opposition Labour Party says it will call a no-confidence vote in the government if the deal is defeated in an attempt to trigger a general election.
The party has not disclosed the timing of such a motion, which could come as soon as Tuesday night. Labour leader Jeremy Corbyn told colleagues on Monday that a no-confidence vote was "coming soon.