The nuclear question on the Clyde
On the banks of the Clyde, some of the most powerful weapons mankind has ever known are based at Faslane Naval Base.
The UK Parliament has backed renewing the Trident missile system. Ministers in London have said they have no alternative to Faslane - the weapons are staying in Scotland.
But that's controversial. The Scottish government wants nuclear weapons moved from Scottish waters. And when the House of Commons voted on renewal, all but one of the MPs representing Scottish seats opposed.
We visited Helensburgh, the booming town where many residents think the economy has benefited from the presence of the base.
Brian Keating runs the local community cinema - with some funding for the facility coming from the Navy.
"This upsurge of economic activity around the navy has been an opportunity to develop other economies here.
"There's all kinds of consequences that are unseen that have occurred because of the investment and because of the growth of the navy in the town."
Just down the road, Will Smith is hosting the official opening of his new restaurant. He's moved up from London, where he'd run successful venues in Soho for years.
"For me the naval base is very important. I believe there's about 6,500 people employed there now - and about 2,000 to come over the next few years.
"Trident's been signed off for the next 10 or 15 years which gives it security, which encourages people like myself to come into an area knowing that you've got that core of people."
Not everyone's convinced. Just beside the Faslane base is a Peace Camp, which has been in operation since 1982.
Chloe, one of the activists living here, tells us: "The cons are a lot greater than the pros... people say it's a deterrent but it's actually just turning us into a target".
Her anti-Trident views are shared by the man who won this seat in 2015 - the SNP's Brendan O'Hara.
As the SNP's defence spokesman, he's been a vocal opponent of trident renewal at Westminster.
He still wants that scrapped, but thinks Faslane should remain open if that happens: "The SNP has never and will never advocate the closure of Faslane.
"Faslane is a magnificent facility - it's a state-of-the-art facility and it can be whatever a government decides that facility should be."
Mr O'Hara thinks it should be a conventional base for "ourselves and our allies".
That's not a view shared by his Conservative challenger Gary Mulvaney. Yes, he agrees conventional defence is important. But he thinks the renewal of trident is important - militarily and for the local economy.
But, we asked him, would he support a Conservative prime minister pressing the nuclear button?
"If we needed to launch Trident I would be very comfortable with Theresa May taking that decision. But primarily that's not what Trident is about - Trident is about defence, it's about deterring people striking at you."
The other two candidates here support renewal too.
Labour's Michael Kelly used to be against trident, but not now.
"I've actually changed my mind - I've come to the conclusion in many ways they are better than other ways of spending our money."
The Liberal Democrat candidate is Alan Reid, who was MP for the area between 2001 and 2015.
"Faslane is definitely the ideal place in Britain to base the nuclear submarines - Trident is the ultimate deterrent against the country being attacked," he said.
"But we also have our duty to play our part in the world."