If a week is a long time in British politics, as former prime minister Harold Wilson famously said, then three months in an eternity. Back in July, then newly crowned UK premier Theresa May visited Edinburgh on her first official engagement. In the Scottish capital she spoke of "the special union" between Scotland and England.

There are no such warm words between May and her Scottish nationalist counterpart Nicola Sturgeon these days. At the Conservative party conference last week, the British prime minister said she would "never allow divisive nationalists to undermine the precious union." Scotland's first minister responding by accusing May of failing to listen to Scottish fears about leaving the European Union.

Brexit - and a possible second referendum on independence - will be uppermost in the minds of the 3,000 or so delegates at the SNP conference starting Thursday in Glasgow. On paper, the UK's vote to leave the European Union looks like a boon for Scottish nationalists. Scotland - alongside Northern Ireland- voted to remain in June's referendum, and the SNP vocally backed staying in the EU.

The 'leave' vote shook British politics. On the morning of the result, Sturgeon, flanked by the starry EU standard and the Scottish saltire, announced that a second independence referendum was now "highly likely."

Coming from a politician noted for caution, such words were a hostage to fortune - but in the febrile post-Brexit atmosphere they felt, even to some Scots who voted no to independence in 2014, like the only proportionate response. Middle-class Scotland, in particularly, is firmly pro-European: Almost three-quarters of Edinburgh voted to remain.

So far, however, Scottish anger at being taken out of the EU has not translated into a clamor to leave the UK. After an initial post-Brexit bump, support for independence is roughly where it was in 2014, when 55 percent opted to stay in UK. Almost as importantly, more than half of Scots do not want another referendum.

'No opt-out for Scotland'

Although the SNP lost in September 2014, the referendum transformed the party. Almost overnight membership quadrupled to 100,000 and is still growing. The grassroots are more pragmatic than given credit for - despite the influx of new, more leftwing members - but many would welcome another shot at independence. England's difficulty could be Scotland's opportunity.

For her part, Sturgeon last month unveiled a new "conversation" on independence. Party members have been charged with convincing 'No' voters to reassess the SNP offer. A "growth commission" will be established to answer the hoary economic questions - most notably on currency - that dogged the 2014 'Yes' campaign.

At the same time, nationalists have maintained that they are open to a deal with Westminster on the EU. Sturgeon and her Brexit minister, Michael Russell, have hinted that some fudge might be possible, perhaps with Scotland staying in the single market and safeguarding freedom of movement.

Such a compromise now looks impossible. Theresa May at the Conservative party conference in Birmingham last week said that there would be "no opt-out" from Brexit. Scotland will not have any veto when Article 50 is triggered next March.

May's strident British nationalism - which included proposals for firms to list their non-British workers which she later rolled back on - has very limited appeal in a Scotland still scarred by Thatcherism. Indeed, it is likely to make the task of the Scottish Conservatives - whose fortunes have improved of late - far harder. But it has put Sturgeon in a very difficult political position: Either she puts up another independence referendum, or she shuts up and shuffles out of the EU with the rest of the UK.

Questionable finances, weary voters

A motion on a second referendum will be discussed at the conference. Privately many senior SNP figures are wary of another bite of the independence cherry so soon. They are right to be circumspect, says Andrew Tickell, a prominent Scottish nationalist commentator.

"The SNP have to have credible answers to questions about currency and finances. But the SNP are terrible at that. It's hard to have confidence that that work has been done," Tickell told DW.

Certainly the economics of the 2014 independence pitch do not hold sway now. Back then the SNP white paper, essentially the blueprint for an independent Scotland, envisaged funding the costs of the new state using only revenues from North Sea oil.

Oil has collapsed. Tax receipts last year were just 60 million pounds (67 million euros/$74 million), down from over 11 billion pounds in 2011-12. Scotland's deficit - the difference between what the government raises in tax and what it spends - has spiraled to 9.5 percent of GDP. The overall figure for the UK is 4 percent.

Politically, Brexit makes Scottish independence more attractive for more Scots, but it adds layers of complexity to the economic argument. Scotland does around 65 percent of its trade with England. Some nationalists argue that independence would be an opportunity to build new business links. That might be possible but would take time and would be highly unlikely to replace cross-border trade.

Finances are not the only challenge to independence. There is a general weariness among Scotland's over-polled electorate. There have been more than half a dozen major elections in Scotland over the past five years.

Meanwhile, over 30 percent of the SNP's own supporters voted Leave, denting the SNP's confidence in the depth of Scottish support for the EU.

Ultimately the decision on a second referendum will come down to the SNP's power couple: Sturgeon and her husband, party chief executive Peter Murrell. Former leader Alex Salmond has predicted that a vote will be held in 2018, but his predecessor will want to be confident of winning before she calls a plebiscite that could - if she lost - spell the end of her political career at the age of just 46.

These are the kind of headaches many old-timer SNP activists are only too happy to have. For decades, politics meant one thing alone: defeat. Now the nationalists are unquestionably Scotland's party of government. In May, the SNP won an unprecedented third term in power in the devolved parliament in Edinburgh.

Last week, a few miles from this week's conference venue, the SNP won a council by-election in Glasgow's working class Scotstounhill. This used to be a Labour heartland. Despite the referendum uncertainty, Scottish nationalism has seldom been so confident about its future.