Without doubt the event will be better supported than a No "rally" staged outside the Senedd yesterday. This was organised and addressed by Dan Snow, the BBC's youthful military historian and latest all-purpose presenter. Snow is married to the second daughter of the Duke of Westminster, one of the largest landowners in Scotland. Around seven people showed up, and most of those were apparently bussed in Labour staffers, keen as young Daniel is to support his father-in-law's hereditary privileges and property interests.
A rather more interesting debate on Scottish independence took place last night on Radio 4, where James Naughtie hosted a meeting of Scottish voters at the Edinburgh Festival drawn from various civic groups. Unlike a lot of the BBC's coverage, this was a much more balanced affair; if anything the Yes camp appeared to have the edge.
The programme, available for a few more days here, is worth listening to. None of those taking part was a politician or political insider, and two things came across very clearly.
The first was the strength and distinctiveness of Scottish identity. Scotland really is a different country - something that is all too easy to forget for the rest of us who rely on Dan Snow and the rest of the London-centric media for our view of the world.
The second was the quality of the debate and the extent to which ordinary people have become engaged in it. Speaker after speaker, from the Yes, No and undecided camps, said how the referendum campaign had caught people's imagination and brought political discussion to life.
If the 'Better Together' campaign had had its way, this debate would not be taking place, of course, and whatever happens on 18 September, this flowering will be one of Alex Salmond's greatest legacies.
As we look forward to September, the rally in Cardiff and the vote itself, here is a short film featuring some of the best and brightest in Welsh life sending their messages of hope and support to Scotland.
Ewch amdani Alba!