Sturgeon's going for a multi-pronged approach with this:
1: She's sent a
letter to the UK Gov. asking for a
Section 30 Order.
2: She's referred the question as whether or not Holyrood can hold such a referendum on it's own accord to the UK Supreme Court.
3: If the referendum is denied, either by the UK Gov and/or the Supreme Court saying Holyrood can't do so within it's remit, then come the next UK General Election the SNP will fight that election on the single issue of independence, thus turning it into a referendum.
The indyref2 questions facing the Supreme Court
Election win should trigger Scottish independence, says Sturgeon
All very convoluted, but all we can do is wait-and-see.
As for the EU angle, I'm not so sure. Some of the Nat diehards may want to see some pressure exerted, but the best thing would be for the EU to adopt strict neutrality.
Mike.