THE pro-independence Scottish National Party (SNP) spent Britain’s general election campaign pledging to shake up Westminster. Having won 56 of Scotland’s 59 seats, it is making good on the promise. In the few days since the House of Commons reconvened, its representatives there have colonised Labour MPs’ favourite bar, defied a ban on taking photos in the chamber and, egalitarian to the core, refused to use a section of the Thameside terrace reserved for MPs (“Now there’s no room for the rest of us!” complains one staffer). Despite losing last September’s referendum on secession, the party is riding high back in Scotland, too: it runs the devolved Scottish administration and counts one in 50 adult Scots among its members.

Yet the SNP now faces a quandary. Throughout the party it is assumed that Scotland will eventually break from the United Kingdom. But members and strategists fret: when? “The worst thing that could happen would be another No vote,” warns one activist, adding that for Scotland to succeed as a separate country voters must opt for that outcome resoundingly—not with 51% in favour, but 60% or 70%. Two camps are emerging: one that wants another referendum at once, and another that wants to bide its time.

On the latter side are most of the party’s upper echelons (probably including Nicola Sturgeon, its leader and Scotland’s first minister). They think the party should spend the next years consolidating its position before asking for a mandate for a new referendum at elections to the Scottish Parliament in 2020. Their watchword is caution, recalling that in the run-up to last year’s plebiscite the “Yes” to independence campaign assured Scots that they had a “once in a generation” chance to leave the union. Scottish voters—55% of whom declined the opportunity—have not forgotten that. When Ms Sturgeon refused to rule out a new referendum in a televised debate in Glasgow last month, the audience booed.

Demographic factors also militate for patience. Younger Scots are the keenest on independence. If this is a generational phenomenon (and their views do not become more conservative as they get older), the thinking goes, the electorate will gradually tilt towards secession as the years pass.

And the SNP can edge Scotland towards independence incrementally. Already another round of devolution is planned. Following promises of further autonomy made by unionists during the campaign last year, David Cameron, the prime minister, appointed Lord Smith, a Scottish peer, to work out the details. Mr Cameron’s Conservative government will now write his proposals—which include devolution of income-tax rates and bands, air-passenger duty and certain welfare benefits—into law before the end of the year, making Scotland about as self-governing as subnational units in federal states like Switzerland and Canada. Ms Sturgeon wants to go farther: she is using her party’s new strength in Westminster to push for control of corporation tax and national insurance (paid by employees and employers), for example, with which to boost Scotland’s finances. Her party claims this could even pave the way for full fiscal autonomy—though it concedes, vaguely, that this could take “a number of years” to implement.

Others in her party see this as a distraction, and want the SNP to seek a mandate for a new referendum at the Scottish Parliament elections next year. The impatient wing includes old-timers who have waited many years for the chance to make Scotland independent, and new joiners drawn to the party by the thrilling experience of last year’s vote. Judging by his triumphalist rhetoric in the aftermath of the general election, it also includes Alex Salmond, Ms Sturgeon’s predecessor.

This camp worries that further devolution could weaken the party—both undermining its claims that its hands are tied by Westminster (a get-out that enables it to combine left-wing rhetoric with a centrist record in Edinburgh) and forcing it to make unpopular spending cuts or tax increases as subsidy from London is withdrawn. “All the burdens of independence with none of the benefits,” says Robin McAlpine, a leading figure on the pro-independence left.

Disuniting the kingdom: A guide to who can claim what if Scotland secedes Moreover, the SNP’s leadership must keep the party’s vast membership happy. “You could sense the power,” says one supporter of the party’s annual conference last November, adding that it seemed to rest not among the “nervous” bigwigs on the stage but in the 3,000-strong crowd. Continually meeting activists’ expectations—which include an end to spending cuts and escape from the clutches of London—over several years will be a slog. Perhaps wiser to go for a new referendum straight away, harnessing their fizzing energy before it dissipates. Finally, the SNP’s superiority over Labour, the party that has dominated Scottish politics for decades, is now crushing. Not used to defending seats it had long taken for granted, the Scottish Labour machine went into meltdown in the days before the election. “We’re in a bad, bad place,” says one campaign chief. After only narrowly surviving a vote of confidence, on May 16th Jim Murphy, the party’s leader in Scotland, tendered his resignation. The temptation for the SNP to push for independence while the main unionist party in Scotland is in the doldrums is strong. Will Ms Sturgeon give in to it? Torn between the wait-and-see tendency and the go-for-it brigade, she will probably split the difference, pledging to hold a referendum if Britain opts to leave the EU (Mr Cameron has pledged to hold a vote on the matter by the end of 2017), but otherwise reopening the independence debate only once the following Scottish Parliament election, in 2020, draws near. Scotland’s opposition must shape up, fast. Deserted by its members and dismissed by voters as a spineless front for the London establishment, Scottish Labour urgently needs to loosen its ties to the Labour Party in Westminster and nurture its withered campaigning infrastructure. Its MPs who lost their seats in this month’s election should not stand for the Scottish Parliament next year; instead the party needs new, hungrier candidates, willing and able to hold the SNP to account.

Unionists more broadly must start preparing for the next Scottish referendum. It increasingly looks as if the only sustainable future for the United Kingdom involves federalism: separate administrations for England, Scotland, Wales and Northern Ireland. The Scots are modestly more left-leaning than the English and want to rule themselves. The English resent the money they pay to Scots and the influence of Scottish MPs in Westminster. Unionists must reshape the union accordingly, or the SNP will end it altogether.