Why can’t there be an English Nicola Sturgeon? That was the cry three years ago, in the wake of her stellar performance during the election debates, although it’s fair to say the shine has worn off since both north and south of the border. Yet this new Brexit crisis threatens to bring it back with a vengeance.

The sheer exasperation with which she challenged Jeremy Corbyn to get on with either trying to trigger the general election he says he wants by calling a vote of no confidence in Theresa May, or to stop hiding behind that excuse and back a second referendum, will resonate deeply with many remainers. Enough with the empty posturing about how he’d be ready to take over Brexit negotiations tomorrow if it came to it, when at this rate it will surely never come to it. So long as Labour flaps around feebly insisting that now isn’t the time, suspicion will persist that it never will be the time; that all Corbyn really wants is to sit back and let Theresa May take the blame for whatever unpopular decision will be needed to break the parliamentary impasse. If not now, with the government collapsing around our ears, then for heaven’s sake when?

Like all the best political questions, Sturgeon’s is all the more unanswerable for being hideously opportunistic. Labour actually has a perfectly legitimate excuse for not calling a vote of no confidence now, although embarrassingly it’s the same excuse May has for not calling a meaningful vote on her Brexit deal; it almost certainly wouldn’t win. The DUP is still supporting the prime minister, and until they’re ready to abandon ship, practically speaking it’s fairly pointless. True, there’s nothing stopping Labour from calling another vote of confidence if the first doesn’t succeed, but a string of failed attempts to chisel her out wouldn’t provide the same springboard for any ensuing general election.

It’s only fair to point out, too, that all this is easier for Sturgeon than it is for Corbyn. After all, she doesn’t have to lie awake at night worrying about the wrath of leavers in Middlesbrough or Hartlepool if their will is overturned. Scotland voted to remain, the SNP is not as divided over Brexit as other parties are, and it does her domestic prospects no harm whatsoever to be seen to be one step ahead of the Labour party in fighting it.

But politics is all about opportunism, recognising the moment when it comes and ruthlessly exploiting it. However much May doesn’t want one, parts of Downing Street seem to be reluctantly coming to the conclusion that a second referendum might be unavoidable. (Although she had other reasons for pulling her meaningful vote, one side effect of doing so is that her deal could still just about be put to the people in a referendum; that would be infinitely harder had it already been thumpingly defeated in parliament.) There is an uncomfortable truth to Sturgeon’s charge that Labour is now the “biggest barrier and stumbling block” to a second referendum, its leader having had to be dragged kicking and screaming to the point of accepting that this could even be an option.

Corbyn’s goal-hanging strategy of letting someone else put in the hard yards over Brexit, before swooping in to electoral glory when it all goes wrong, has served him very well for two years. But the closer we inch to inflicting irreversible damage, the more cowardly it looks. You don’t have to agree with Sturgeon’s politics to agree with her that this is one of those moments when a nation rightly expects politicians to step up, not mill around waiting for someone else to go first.

For all her flaws, Sturgeon’s strength is and always has been clarity of purpose. She knows what she wants, has the guts to go after it when an opening arises, and can speak sufficiently fluent human to communicate it even to people sick of hearing about Brexit. That the same cannot be said of either Corbyn or May is both a reflection of the state we’re in, and a bad omen for what may follow. What is painfully absent in this crisis – apart from a workable solution to an impossible problem – is leadership. The reason people respond as they do to Sturgeon is that she reminds us what that looks like.

• Gaby Hinsliff is a Guardian columnist