Given the referendum was meant to be about restoring British sovereignty, in one respect Leave campaigners should be delighted by the High Court's ruling.
Surely this is what they want? Parliament taking back control?
This is, of course, unlikely, when the Commons is stuffed full of pro-Remain MPs. But few are seriously talking about using the Brexit legal challenge to reverse the referendum result. Instead, they'll use it to try to soften the terms of our departure from the EU.
Theresa May, a Remainer (on paper at least) during the referendum campaign, decided the result gave her a personal mandate to not only take Britain out of the EU, but determine the precise form of that departure, and its timing.
The court disagrees, and unless the Government's appeal succeeds, that means MPs will get a vote before Article 50 is triggered -- but what kind of vote?
A whole new bill, requiring line-by-line analysis, would make painfully slow progress through the Commons and Lords, derailing Mrs May's timetable.
Instead, she could try what's called a substantive motion -- a straight yes or no on the question of triggering Article 50. That's much quicker, but may not be in compliance with the court's ruling that MPs must be consulted.
The Prime Minister made a strategic blunder by trying to sideline Parliament, and made a further mistake by claiming her opponents seek to ignore the will of the people.
MPs know they can't afford to overturn the wishes of 17-million voters. Even the most passionate Remainers will, in the end, accede to Britain's departure from the EU. But they may want to soften the terms of Brexit, hanging on to as much free trade and free movement as they can manage.
If they're serious about this, they'll need to adopt their enemies' strategies.
Who are the bastards now?
Remember John Major's "bastards" -- hardline anti-EU campaigners like Iain Duncan-Smith, who exploited the Conservatives' wafer-thin majority in the 1990s, and helped push the party out of office for 13 years?
Mr Major struggled with a majority of 21, and MPs who would rather have seen a Conservative government fall than see Britain sign up to the Maastricht Treaty.
Theresa May's majority is even smaller -- an opportunity for pro-EU Tories to demand concessions on Brexit.
Whether that happens depends on how willing those Tories -- people like Anna Soubry and maybe even George Osborne -- are to threaten the Government's survival. Tory party members are far more pro-Brexit than many of the MPs -- and that will keep many potential rebels quiet.
The nuclear option
There is one other way for Mrs May to get a clear mandate to deliver Brexit on her own terms -- an early General Election.
She's repeatedly ruled that out -- but that was before the High Court intervened.
Two-thirds of MPs would have to approve an early election -- for Labour that would have a certain "turkeys voting for Christmas" feel -- but if the last year has taught us anything, it's to expect the unexpected...