Just when you thought the Brexit misadventure could get no worse, the speaker of the House of Commons stepped forward to turn it into a constitutional farce. What else can go wrong, one wonders, between now and March 29, the U.K.’s designated date to leave the EU?

Thursday may provide an answer. Prime Minister Theresa May is to meet the European Union’s other leaders and ask them to extend the Brexit deadline. They’ll need to ask her what purpose a delay will serve. Then, exasperated as they must be, Europe’s leaders should guide her toward the best course.

This doesn’t mean they should help her revive the previously negotiated withdrawal agreement, as she seems to intend. That would serve neither side’s interests. Leaving the EU on those terms would harm Britain’s economy and still fail to provide the political autonomy that leaving was meant to achieve. And although Brexit would hurt the U.K. far more than Europe, Britain’s departure would weaken the EU, both internally and externally, just as the union’s strength is being tested in other ways.

It isn’t too late for Britain to think again. And although the responsibility in this lies entirely with Britain, the EU can help — by leading May toward a Brexit delay that’s long enough to allow a fundamental rethink and a second referendum, rather than a short extension aimed at reviving the deal that Parliament has twice rejected.

Bear in mind, that deal isn’t yet dead — despite the earlier defeats and even though Speaker John Bercow has bizarrely denied Parliament permission to vote on it again. His ruling was indefensible, since the speaker’s duty is to facilitate the will of Parliament, not thwart it — and it can be overturned. If a majority emerges in support of May’s deal, that same majority can override the speaker.

Unfortunately, the prime minister might yet assemble such a majority, once MPs finally realize that without it, the only remaining options are a cliff-edge Brexit or no Brexit at all. Europe should not help May execute this strategy, so long as it’s still possible to prevent Brexit altogether.

And it is. Everybody understands that the Brexit May proposes is not the Brexit her country voted for in 2016. A second referendum is needed, not to throw the voters’ verdict back in their faces, but to let them think again now that the meaning of Brexit is clear. The idea is to facilitate their will, not thwart it.

Europe’s leaders ought to refuse a short deadline extension but allow a longer one. They need not make another referendum a condition for granting it, but they should urge May to open her mind to it, and insist she not rule it out.

Granted, further delay means continued uncertainty and more costs. It also involves complications — including that Britain would have to take part in European Parliament elections scheduled for May. Yet the potential for no Brexit is worth it.

After all that’s happened, Britain can’t expect to appeal to Europe’s generosity. But Europe’s governments still owe it to their own citizens to do what they can to help Britain regain sanity, return to orderly government, and avoid making this historic error.