Scottish Referendum Legislation: Supreme Court Decision

The Supreme Court today did not rule that Scotland should not be independent or that Scotland should not be able to have a referendum; it ruled that the existing legislation written by Unionist politicians does not allow the Scottish Government to make that decision, unless the UK Government are willing to amend it, as they did in 2014. That is the legal argument.

I want to know what the democratic argument is against Scotland being able to do that. In the Scottish Parliament elections—one of the eight elections we have won since 2014—not only did the SNP leaflets say, “Vote SNP for a referendum on independence”, but the Tory leaflets, the Labour leaflets and the Liberal Democrat leaflets all said it. What is the democratic argument against Scotland and the people of Scotland being able to simply answer that question?