It may seem a peculiar thing to say about a broadcast that virtually from beginning to end was devoted to listing a roll-call of the Tories' crimes against Scotland in the 1980s and 90s (even at one point evoking the spectre of 'Maggie Thatcher Milk Snatcher' from the early 70s), but Scottish Labour's PEB last night was all about an attempt to defuse the threat from the SNP. It's rather like thinking up a joke - you start with the punchline and then build the rest of the joke around it. The single line the creators of last night's broadcast will have started with is "this election is a two-horse race" - which, presumably, is the only line of attack against the SNP's positive message that Labour are confident will have the slightest traction. It doesn't say much for Labour's faith in how their pitch for votes would fare in a straight comparison with the SNP's that they so obviously feel their best hope lies in bypassing all that and instead browbeating the voters into thinking the SNP aren't 'really' a choice in this election at all.
So all that the rest of the PEB really tells you about is the context in which Labour's creatives felt they could place their key line for maximum effect, ie. the reaction they hope for is "oh yes, the Tories must be stopped at all costs, so if this election really is a 'two-horse race', I must make sure I back the horse that isn't Tory...wait a moment, doesn't that mean voting Labour and not SNP?". Talk about treating the electorate like children.
In truth of course, all this talk about 'two horse races' is an utter nonsense in Scotland's four-party politics. Due to the inequities of the majoritarian electoral systems so beloved of both Labour and the Tories, many constituencies do indeed have only two candidates who can win - but in only in a tiny minority of cases is that choice between Labour and Tory. If stopping a Tory government is the only thing that counts in this election, how would Labour advise people to vote in, for example, SNP/Conservative marginals like Perth and Angus? There can only be one credible answer. Small hint - it isn't Labour.