Returning to Scotland earlier this year, I counted every Union Jack I saw in the country. It wasn’t difficult. Beyond a few government buildings in Edinburgh, I noticed exactly zero Union Flags while traveling through the Highlands, Argyll, and Ayrshire. In contrast, Saltires were prolific, and I even found unauthorized use of the Lion Rampant. Altogether, I counted more EU flags than UK flags in Scotland (and later more American flags in Dublin than UK flags in Scotland). The result didn’t surprise me, and this unofficial survey reminded me of a Scottish university student’s divisive and extreme quip: “Only a—s wave Union Flags in Scotland.”

Such a deficit of British nationalism also reminded me of C.S. Lewis’ remark that “only foreigners and politicians talk about ‘Britain’” while discussing how Christians can love their country well. Given the vast majority of people living in the UK outside London and Northern Ireland say they’re English, Scottish, or Welsh when asked about their nationality, British nationalism is arguably weak, particularly after the end of empire. Yet in the US I often hear claims that Brexit is a British nationalist project, especially from those on the Right who applaud the UK leaving the EU. (In British media meanwhile, I usually see the word nationalist connected to Scottish independence, something Americans who like Brexit usually disdain.) More precisely, Brexit is about English populism, not British nationalism. And while Prime Minister Boris Johnson harnessed this populism to win last week’s general election decisively, its English nature threatens the union’s survival. Some have even discussed whether he could become the last prime minister of the United Kingdom of Great Britain and Northern Ireland.

In the north where a Union Jack can rarely be found, the Scottish National Party (SNP) renewed calls for a second referendum on Scottish independence (IndyRef2) after its general election victories. Not only did the SNP oust Liberal Democrat leader Jo Swinson, a unionist who opposed Brexit, it also reduced the Conservatives from 13 seats to six and Labour from seven to one while winning 48. The first IndyRef occurred in 2014 when 55 percent of Scottish voters chose to stay in the UK, but 62 percent of Scottish voters opposed Brexit in the 2016 referendum and will be pulled out of the EU next month. Opinion polls therefore show Scotland could vote yes for independence.

Arguing Brexit changed Scotland’s circumstances after the first referendum, SNP leader and First Minister of Scotland Nicola Sturgeon released a 38-page document last Thursday detailing why her nation should be independent. She said while presenting it:

In a voluntary association of nations such as the UK, it cannot be in the interest of any part for our right to choose our own future to be conditional, or time limited, or a one off. Nor is it right for it to be overridden by a prime minister, or indeed a first minister. It is a fundamental right of self-determination.

 When addressing how Johnson will inevitably refuse another referendum, Sturgeon responded:

It is for the prime minister to defend why he believes the UK is not a voluntary union of equal nations. It is for the prime minister to set out why he does not believe people in Scotland have the right to self-determination. It is for the prime minister to explain why he believes it is acceptable to ignore election after election in Scotland and to override a democratic mandate stronger than the one he claims for his Brexit deal. The Conservatives’ only response to this, so far, has been the referendum result in 2014… The Tories are in effect saying to people here that democracy in Scotland stopped the day we voted No in 2014.

Prime Minister Johnson has repeatedly promised he wouldn’t allow a second referendum, saying the first was a “once-in-a-generation event.” And according to the Scotland Act 1998, which gave devolved powers to the Scottish Parliament in Holyrood, the UK Parliament in Westminster must grant a section 30 order for Scotland to hold a legal independence referendum. Since Johnson adamantly refuses to grant one, the discussion should be over, at least for five or ten years.

Yet some hardline Scottish nationalists propose their nation could become independent without a section 30 order. For instance, one argument suggests because the UK is a voluntary union of Scottish and English parliaments, Scotland would become independent constitutionally if Scottish MPs left Westminster. So a section 30 order would be nice for legitimacy but is unnecessary according to this perspective. Nevertheless, an IndyRef2 without a section 30 order would be risky—and not just because the European Union, which Scotland wishes to join, may dislike it. Given the UK’s messy, unwritten constitution, the courts would have to decide what rights Scotland has. The nationalists could eventually face a Catalan situation if the courts decided against them. As a Plan B, using the courts is naturally worse than Plan A, receiving a section 30 order.

Sturgeon remains focused for now on a section 30 order she knows Johnson won’t grant. According to BBC’s Scotland editor Sarah Smith, the first minister’s message is for Scottish voters, not the prime minister. The SNP leader wants to prove Westminster is denying Scotland democratic rights so that more Scots will support independence. The SNP followed a similar strategy in the 1990s while arguing for years the country needed its own parliament to prevent English MPs from ruling over them. Ultimately, 74 percent of Scottish voters said they wanted their own parliament in a 1997 referendum. If Sturgeon’s strategy succeeds, independence could become the “settled will of the Scottish people,” which isn’t so now. Polls show more Scots support independence today than in 2014, but the split remains 50-50. A worst-case scenario would be if, say, only 52 percent of voters chose to leave the UK. One could imagine how national unity might disintegrate with such a slim victory, or wonder what would happen if opinion polls shifted back toward remaining in the union. For such radical constitutional changes, a higher bar should be necessary, as amendments to the US Constitution require. If Sturgeon’s strategy convinces the vast majority of Scots to support independence, the country would meet this bar and fare better after independence.

Because Boris Johnson won’t grant a section 30 order and Nicola Sturgeon is playing a long game, he will probably not be the last prime minister of the United Kingdom of Great Britain (Northern Ireland, which this article doesn’t address, is a different question). But he still risks becoming the next-to-last UK prime minister or one who leads Britain closer to dissolution.

Nevertheless, Prime Minister Johnson remains committed to preserving the union and even made himself “minister for the union.” His dedication appears stronger than that of other English Conservatives, who are often irritated with Scottish nationalists and may be willing to let Scotland go. Yet Johnson’s wooing of Scotland mostly emphasizes economic motivations for union. For instance, in an interview with the BBC he emphasized how his government improved Scotland’s economy while the SNP implemented high taxes and produced poor results on health and education. He also renewed the idea about building a bridge, the “Celtic Crossing,” linking Scotland with Northern Ireland. And the Scottish Tories’ 43-page manifesto, “No to IndyRef2,” includes a long list of materialistic goodies from Westminster—free trade deals, agriculture subsidies, an infrastructure revolution, etc. But the manifesto does not adequately describe deeper British identity or values that would suffer if Scotland left—at least not much beyond a brief mention buried deep on page 38 about the UK’s role in ending the slave trade. Surely Conservatives can say more about Britain’s greatness beyond its currency and business climate.

Appealing to the Scots’ economic interests makes political sense. Fears that an independent Scotland would be poorer convinced many Scots in 2014 to stay in the UK. Besides, other non-economic proposals have failed for now: an Act of Union Bill would have turned the UK from a unitary system (where Westminster controls most policies) to a federal one (the British nations would be more like US states), but the bill died. Yet while economics mattered greatly in 2014, now may be different. First, Brexit means Scotland could face economic risks whether it remains in the UK or not. Second, Scottish voters could decide to accept economic damage to achieve independence, just as Tories were willing to do so for Brexit. Voters aren’t always homo economicus and may choose to suffer for higher ends.

If Boris Johnson wants to preserve and restore the union, he needs to do more than appeal to economic and materialistic interests. He must promote a more profound British narrative and identity. Even though C.S. Lewis suggested “Britain” mostly exists in the imagination of foreigners and politicians, he did describe a healthy patriotism and love of country the prime minister could emulate for the UK. Instead of merely accepting the cold calculation that staying in the union means maybe slightly larger paychecks, more and more Scots may come to love the union again. They might even wave the Union Jack alongside the Saltire.

Is Johnson the right figure for this task? Considering the SNP victories over unionists, he may not be but can still adjust. If Johnson responds successfully not only to English populism and Brexit but also Scottish nationalism, he would arguably become one of the great prime ministers of British history.