By Martin Geissler: ITV News Correspondent
The Prime Minister's trips to Scotland are always fascinating to watch.
There's so much to analyse when David Cameron comes here; not just what he says, but where he says it and who he says it to.
There's a perception the PM is scared to meet "real" Scottish people in front of the cameras, terrified they might actually tell him what they think, and there's plenty evidence to support that claim.
So far this year Mr Cameron's Scottish visits have taken him to a conference hall full of Tories, a rig hundred of miles offshore and a boardroom in the secure compound of an oil firm.
This afternoon he visited an army barracks. He's not exactly "living on the edge" when it comes to engaging with the electorate.
But, realistically, what else can he do?
Today he's in Glasgow, a city of a million people who haven't elected a single Tory MP since 1979. A walkabout up Sauchiehall Street would be electoral Russian Roulette.
So he plays it safe. Arrives, stamps the passport, then leaves. No messing around, get the job done and get out, a bit like the SAS.
He'll be criticised for that, of course, but he'd be criticised if he didn't come too. He's choosing the least worst option.
There is business to be done up here, no doubt. Mr Cameron wanted the referendum to to be a done deal by now. He finds the thought of the Union disintegrating on "his watch" terrifying, it's said.
But he has a problem, his supporters in Scotland - and there are more than you might think - already know how they'll vote come September.
It's Labour followers he needs to win over, and when it comes to attracting them, less is definitely more if you're a posh southern Tory.
So, he leaves it to Scottish Labour to sort out, right? Well, perhaps. But Alistair Darling's stewardship of the "Better Together" campaign hasn't been a rip-roaring success so far.
The unionists thought apocalyptic warnings on currency and Europe would kill the debate stone dead. In fact, they had the opposite effect - many Scots railed against what they saw as "bullying" and sided with the nationalist "Yes" campaign.
There are still a million undecided voters here, more than a quarter of the likely turnout. They're the people who'll decide whether this kingdom remains united.
Mr Cameron has to walk a tightrope, winning support is one challenge, but not losing it may be just as tough.