virus that doesn’t care about nations or history can still spread borders across the map like a rash. Different European countries’ pandemic responses restored boundaries that were meant to be submerged for the cause of continental integration. That effect was less pronounced within the UK, but public health is a devolved matter, so lockdown has probed the tender line where England meets Scotland. There is no Scottish plan to quarantine visitors from England, but Nicola Sturgeon has refused to dismiss the notion completely. Opining on the subject in parliament last week, Boris Johnson offered the untrue and crass assertion that “there is no such thing as a border” between the two nations. The inane gauntlet was taken up by a handful of pro-independence activists over the weekend, who stood at the sign on the A1 welcoming motorists to Scotland with a banner urging the coronavirus-carrying English to stay away. Sturgeon condemned the stunt as not “sensible or helpful” and no doubt she meant it. The first minister is a nationalist but not an Anglophobe fanatic. Her method for dismantling the union has been to entrench SNP control of devolved institutions until it is hard to distinguish party and state. The pursuit of independence then becomes a settled fact about what it means to be the government of Scotland, thus disqualifying pro-union parties. Anyone who doesn’t want independence has to work harder just to join conversations about Scottishness and the future. It is working. The defeat of the “yes” campaign in a referendum has faded in the historical record more than it should for something that happened only six years ago. That whole world looks hazy now through the volcanic ash of subsequent political eruptions – Brexit, which a majority of Scots opposed, then the pandemic. The coronavirus emergency boosted the standing of incumbents in most countries, but that “rallying to the flag” effect has been stronger and lasted longer in Scotland than in England. Even many of Sturgeon’s critics privately concede that she has had a good crisis, leavening executive authority with humility and sincerity – qualities the Tory leader has only read about. The first minister’s personal ratings have soared, which is doubly remarkable since she began the year looking stale in office and unsettled by charges of sexual assault hanging over Alex Salmond, her predecessor and former mentor. (He was acquitted, but the political wound is still open.) Opinion polls show regular majorities for independence, although that masks a common lack of enthusiasm for re-enacting a referendum battle that divided families and polluted friendships. Sturgeon has to appeal to a mainstream that prefers the rhythm of normal government to the relentless beat of the separatist drum, while at her back is an impatient SNP faction that suspects her of getting too cosy with the status quo. It is a sign of how badly the pro-union side failed to embed its victory that the debate on independence is a three-way tussle between “yes, now”, “yes, later” and “let’s not have this argument”. No party is challenging the SNP for control of Holyrood. Labour’s ambitions are limited to winning back second place from the Tories who have stagnated since losing Ruth Davidson’s leadership. Between now and next May’s Scottish parliament elections, Britain must pass through more Brexit turbulence; transitional arrangements expire on 31 December. In every scenario, the SNP then complains that English Tories have wrenched pro-European Scots from their home continent without consent. Barring some unforeseen political accident, Sturgeon will then be confirmed as first minister, arguing that her refreshed mandate compels Westminster to legislate for an independence referendum. Johnson will refuse, thus vindicating the nationalist view that Tory England always represses the will of Scotland. But the prime minister might prefer that charge to a gamble on having his remaining time in office consumed by a battle to save the union, and possibly ending up in posterity as the man who broke the kingdom. Downing Street’s Plan A to dampen the clamour for independence was hosing Scotland with public money, but competition for that resource is getting more intense and areas with Conservative MPs are the priority. If there is no sign of a Tory revival north of the border, an even more cynical path might appeal: letting the flames of resentment roar in Scotland, igniting a Johnson-supporting English nationalist backlash. All the better if that sustains the toxic question of whether Labour needs SNP MPs to support a coalition come a general election. It would take an exceptionally irresponsible prime minister on a streak of constitutional pyromania to pursue such tactics. Johnson is qualified. A conflagration in Scotland might not be the next crisis to destabilise Britain, but it is in the queue. It is also unnerving how little England is prepared, when Scottish politics is a rolling rehearsal. That bodes ill for the pro-union cause. English voters who support neither a Tory government nor Scottish independence have no purchase on a debate that is existential for their country, if that country is identified as the UK. Theirs is the queasiness of the spectator with emotional investment in a contest and no influence on the result. That is how my French and German friends described Brexit, which is disturbing because the comparison feels both apt and ridiculous. There is eerie familiarity in the way the pro-union cause is floundering, but it is madness to imagine a cultural border between England and Scotland analogous to the Channel. But the arguments against separation have atrophied from lack of exercise and the nationalist songs have catchier tunes. The SNP strategy is to make independence feel inevitable. It needn’t be, but divergence is the easier trajectory to plot. Meanwhile, the unionist cause has not evolved beyond hoping Sturgeon is wrong, while deferring the moment of asking Scotland the question directly, which is an admission of fear that she is right. • Rafael Behr is a Guardian columnist