AT least they tried to get the optics right this time.

Labour leader Ed Miliband, one-time visiting scholar at Harvard, will be familiar with the American political jargon. Good optics might include having a photo with Obama or helping out at a charity event. For bad optics, look no further than Mr Miliband's visit to the St James Shopping Centre in Edinburgh last September. As disastrous photo ops go, that was one big bacon sandwich-eating session with extra brown sauce.

The St James Centre, you will recall, was the scene of a walkabout by Mr Miliband during the referendum campaign. Surrounded by highly vocal Yes supporters, young Ed was rushed out of the place as if he had just been caught robbing the charity box. While no-one emerged from that episode covered in glory, Mr Miliband looked particularly wan. It was as good a sign as any that when it came to the mood in Scotland, the Labour leader, and his team in London, did not have a clue.

Sent homeward to think again, he was back in Scotland yesterday with a more optics friendly schedule that included, among other things, a visit to a training centre to meet young apprentices. This was more like it. Something real to hold on to, something concrete to talk about, something with seemingly no connection to the grubby goings on out there in the world of real politics. It is in the latter sphere that Mr Miliband so often encounters trouble. He looks the very dab at Harvard, he sounds competent enough when speaking to a crowd of supporters (provided he remembers his speech), and given the chance he can come across as an affable bloke.

The difficulty for him is that the territory of real politics is the one he has to fight on between now and the next election. This is particularly the case in Scotland. With a hung parliament expected after the next election, talk is now turning, tentatively but increasingly, to the possibility of SNP MPs doing business with a minority Labour government. As a trio of well known political commentators of old might put it: double, double, toil and trouble; fire burn and cauldron bubble. Peering through the steam and noise, inhaling a lungful of the sulphur which so often accompanies any dealings between Labour and the SNP in Scotland, what is Mr Miliband to do?

Yesterday, the laddie was not for turning towards the SNP. This was a straight fight between Labour and the Tories he said, though it was notable that the form of words he used in answer to a question - "We don't need, we don't want and we're not planning for [a deal]" - left more than a little Heseltonian wriggle room should it turn out they do need help.

Mr Miliband has to hang tough. It would be electoral suicide for any major party to go into an election trailing even the merest hint that they might not win outright. Those who look like losers tend never to become winners.

For all that, Labour now realises that at the last General Election it was missing in action when it came to forming a government. The party was simply not prepared for the horse-trading that followed the result. It was slow, stupid, or stubborn. So the Tories and the LibDems did a deal instead. Labour snoozed, and the poor and vulnerable were the ones to lose. Few among the Labour ranks would want to countenance a repeat of that indolence and naivety. Looked at this way, preparing the way for a deal with the SNP, or other smaller parties, is simply good housekeeping, a case of making sure there will be enough votes coming in to cover the Bills.

After all, Labour and the SNP are two left-of-centre parties who share a vision of a just society, so much so that when it comes to criticising Scottish Government policy, shadow ministers are often reduced, somewhat pathetically, to carping: "We would have announced this earlier/later/wearing a different coloured jacket." Labour and the SNP are to be found on the same side on many an issue, including, as we saw this week, fracking. The leader of Labour in Scotland, and the SNP leader, are both as far away from the Eton-educated, privileged-swathed, sharp-elbowed classes as it is possible to travel. All of this being so, and to semi quote the words of the aptly named band War, why can't they be friends?

We pause here to take a deep breath, sucked in over the teeth, and shake the head. In short, to adopt the manner of a particularly sceptical builder being asked to quote on a job. Where to start madam and sir? For a start, you've got that dirty great disconnect on Trident. One side is against it, one is for it as long as the house next door has still got one. No amount of gaffer tape will hold those positions together. Then there is the Union. Same again. Could try something semi-permanent, but the cracks will appear sooner or later. Then there's yer historic, in-with-the-bricks grievances, some of them recent (the Iraq invasion), some them not so recent (SNP MPs helping the Tories to bring down the Callaghan government in 1979, thus beginning the Thatcher era). You cannot plaster over those kinds of cracks, oh dear no. Any chance of a cuppa while we go on? Lovely.

Even assuming, by some miracle, you could repair that lot there are other factors to consider, such as the position of Labour MPs from the north of England and London who already think Scotland has been taking too much from the pot when their constituencies have needs too. They will not want to pay any price the SNP demands. Then there is the wider neighbourhood. Voters in general are never keen on bodge jobs. They tend to take it out on the prop rather than the propped up. The SNP could become as despised as the LibDems. Imagine that.

Finally, there are the personalities involved, and the timescale. Any rapprochement would involve taking two parties, who less than a year ago were at each other's throats (and still are), and asking them to kiss and make up. Two parties, moreover, led or influenced by alpha types who are fond of a scrap the way builders like tea. We know, from Nicola Sturgeon's Barbara Woodhouse-style put down of Alex Salmond this week, that she will take firm charge of any post-election talks. Look what happened the last time she stood nose to nose, lectern to lectern, with a Labour leader. That went well, did it not?

That STV debate encounter was a window on to the world of any post-election SNP-Labour coalition. The bolder Labour supporters know this. Those of a more nervous disposition may yet want to keep their options open, while it suits the SNP to be seen as kingmakers whatever happens. Now is the time for all plain speakers to come to the aid of their respective parties and just say nae chance.