The Liberal Democrats are riding high. Their vastly improved vote share in the European elections, the spate of defections from defrocked Tories and the influx of Remainer ultras to their ranks have boosted their confidence and given them hope of return from the electoral wilderness that followed their five years propping up David Cameron.

The major announcement in Jo Swinson’s closing speech to conference on Tuesday, much trailed, was that the Liberal Democrats – were they to form a majority – would revoke Article 50 on their first day in government, ending Brexit overnight. She decried both Labour and Conservative as ‘tired old parties’, and suggested that Boris Johnson – somewhat perplexingly – was acting like a ‘socialist dictator’, while linking Jeremy Corbyn and Nigel Farage in a feat of rhetorical contortion. As if to prove the Lib Dems’ moderation in all things, she unveiled a lukewarm climate policy, aiming for net-zero emissions by 2045, knocking five years off the government’s goal but giving themselves far more wiggle-room than the target of 2030 due to be debated by Labour next week.

‘The faultline in British politics is no longer a left-right divide,’ Swinson said before the conference. She prefers a division between authoritarian and liberal, or closed and open. The analysis is modish, though its diagnosis has been proffered many times before: it used to be known as the ‘third way’. It seems unlikely that the division between left and right, which has endured as a heuristic since 1789, has met its end in a constitutional squall in a mid-tier North Atlantic former imperial power.

With her parliamentary ranks swollen by MPs originally elected as Labour and Conservative, Swinson’s tap-dance preserves a precarious unity – already under tension from the recent embrace of former Tory MPs. In a Q&A session with party members over the weekend, Swinson tried to hedge over Philip Lee’s support for barring HIV positive immigrants; one heckler declared it a ‘Ukip policy’. Sam Gyimah’s enthusiasm for tax cuts may hew closer to Orange Book orthodoxy than some members like to believe: Swinson’s defence of austerity – in one interview even recycling the hoary Tory cliché of ‘magic money trees’ – should provide some ground for rapprochement. Yet it rankles among the longer-term party base, who fear their social liberalism is an ever-diminishing supplement to Orange Book hegemony. The final calculation may be electoral: whatever the fantasies of the eternally excitable Chuka Umunna, it is vanishingly unlikely the Liberal Democrats will win 200 seats. Their top marginal targets are overwhelmingly Conservative: Richmond Park, Cheltenham, Devon North. Wooing Tory voters dismayed by the Johnson ascendancy must be central to their electoral strategy, though Swinson’s open-door policy for Conservatives may threaten her own seat – Dunbartonshire East was taken by the SNP in the post-coalition Lib Dem wipeout in 2015.

However many her jeremiads against populism, Swinson is not immune from its taint. The cringeworthy ‘Bollocks to Brexit’ slogan that now adorns so many party materials is also the Lib Dems’ chief platform, and their move to outright revocation has been taken as confirmation of their desire to hegemonise the Remain vote. It may also, though, be a sign the party is listening too closely to its newfound Twitter enthusiasts: zeal for outright revocation is far higher among them than it is in the country. And perhaps it is tacit confirmation that the party, for all its outward self-regard as a major force in British politics, still sees itself as minoritarian, catering to a small hardcore of popular opinion.

Were the Liberal Democrats to win enough seats in a general election to form a government, the political argument for revocation goes, democratic consent would have been given for their stated policy and no further consent, in the form of a second referendum, would be required. One objection to this argument is from principle: the Lib Dems have always complained about the unfairness of the first past the post electoral system, which allows a single political force to wield legislative power without a majority in the country. Were they to pursue revocation on such a basis – with far fewer votes than the absolute majority won by Leave in the 2016 referendum – it would vapourise consent among Leavers. It is no less a species of anti-politics than that pursued by Farage, Johnson or Cummings; its outright disdain for compromise and willingness to manipulate electoral structures provides a neat example of the kind of cynicism that Cummings, especially, wishes to inculcate among the ultra-Brexit constituency.

A second objection is strategic. There is little chance the Liberal Democrats will form the next government. The policy is nugatory, vain conference moonshine to flatter and energise the base. Yet its strategic consequences are real: many Leavers are already suspicious that a second referendum of any sort is a ploy to engineer a Remain vote at any cost, and the Lib Dem position will do little to allay fears that a ‘People’s Vote’ is a rickety Remainer Trojan horse. It runs against the popular sense that a policy decided by a referendum could only be reversed by one, too; a sense endorsed by most prominent Lib Dem MPs in parliamentary speeches and election literature before 2016. The Greens’ Caroline Lucas, who has campaigned closely with the Lib Dems on a second vote, called it ‘irresponsible’. Party members must be wondering, too, if so flagrant a position can really pull in the Tory waverers it wants; Labour strategists must at least be smiling that it distinguishes them as the only party set on a second referendum.

Liberalism is a capacious ideology. It can include continental laissez-faire alongside the vague big-government progressivism of its US variety; this ideological flexure allowed Charles Kennedy to present his opposition to Blair’s increasingly war-bent and authoritarian government with a social democratic tinge, and achieve the Lib Dems’ high-water mark of 62 seats in parliament. What’s more, liberalism so dominates the lexis of political thought that even its critics, on both left and right, articulate dissent largely within its terms: rights, the rule of law, representation. Liberals can face the victor’s problem of having to defend the status quo in a world to which it has become startlingly inadequate.

The most cogent critics of liberalism have always challenged its comfortable self-exculpations, not least its tendency to disclaim political responsibility for social strife, or to see its roots as outside the political process. The late Domenico Losurdo, for instance, underlined its dependence on exclusion, and juxtaposed its putative universalism with its recurrent distrust of the franchise and careful policing of the boundaries – class and racial – of the political community. But Losurdo also offered an appreciation of liberalism’s achievements – freedom from arbitrary power, constitutionalism, the gradual accommodation with democracy – to highlight that any progressive successor order would need to guard and extend them. However imperfectly realised, they are especially worth defending against an increasing mania for the trappings of autocracy; such a defence may also be the only honest way to begin accounting for liberalism’s failures.

It’s unfair to expect the weight of an entire political tradition to bear down on a single politician. Yet the lingering sense from Bournemouth is of a leader whose appreciation of the stakes is still too low, sublating all social questions into Brexit policy, with a pallid mimickry of populism in yellow garb. Swinson risks repeating the original sin of liberalism, its policeman’s instinct for narrowing the zone of the politically acceptable, and thus both hampering the party’s political latitude after an election and aiding the arsonists in democracy’s basement.