As they look in the mirror today, MPs must ask themselves this question.
Will I fight to free Britain from the constitutional quagmire it has been stuck in for three long years?
Or will I put animosity and misplaced party loyalties first, and condemn my constituents to endless Brexit torture?
That is the choice for this first Saturday sitting in 37 years. Will it be progress – or further paralysis?
There's no question what the public wants. Exhausted by years of deadlock, our poll shows they've had enough.
Stagnation has become the norm. Worse still, the opposition parties constantly whine that Mr Johnson (pictured) is not fit for office, yet don't have the guts to call an election
Half of respondents believe MPs should approve the Brexit deal today, against just 38 per cent who don't.
And significantly, if it fails, only 21 per cent believe it would be solely Boris Johnson's fault – with twice that number blaming Parliament.
This augurs well for the Prime Minister in a future election – as does the five-point spike in the party's overall poll lead.
But the wider truth is that Britain needs its democratic institutions to start working again. While the Commons has been bickering over Brexit, the things people really care about – the NHS, schools, law and order – are being neglected.
Stagnation has become the norm. Worse still, the opposition parties constantly whine that Mr Johnson is not fit for office, yet don't have the guts to call an election.
So will our zombie Parliament redeem itself by passing this deal?
Sadly, the DUP won't support it because of issues over the new customs arrangements and consent. (This, despite the fact that Lord Trimble, that giant of Ulster Unionism, is fully behind it).
Without them, the Prime Minister must win