It's a very good thing we didn't develope them in 1966, cus we would have been democratized in 1967.
Actually, Canada had the ability to build "the things" after WW-II. It was one of three countries with "the secret", the other two being Uncle Sam and the UK.
Those three had it because: 1) The Manhatten Project was started in England, but they had to get it away from bombing, 2) The US offered to host it, and when dawned the potential, offered to pay for it, 3) Canada was the only allied source of mineable uranium.
At first England and Uncle Sam didn't want to tell Canada what they wanted the uranium for, but Canada's PM was Right Honerable crazy-King... the PM who'd consult the spirit of his dead mother on affairs of state, and she told him the uranium was wanted for a higher purpose... or maybe it was just those physicists from UofT mentioning in more than just an offhand way that if the allies wanted *that* much uranium, there could be only *one* thing they were up to.
So... although the US offered to pay for roads and mines in northern Saskatchewan to dig the stuff, King said, "No... we'll build the roads and mine it and we will deliver it to you at the border, but you *are* going to let us in on what you're up to, because we think we already know!"
And so at the end of WW-II Canada was one of three with the secret of the atomic bomb, caught between Uncle Sam arming up with nukes on one side, and Great Mother Britian (or Evil Step-Mother Britian if you're Quebequois) on the other side, also arming up with nukes, and so Ottawa chose to keep her Royal Canadian *** out of it, focusing instead on peaceful applications, like development of the Candu reactor... still probably the safest in the world... able to run on non-enriched uranium as long as one uses heavy water as the coolant... the only problem being that it produces lots of plutonium as the waste product, which means if Canada were to sell Candus to a non-signature of the Non-Proliferation Treaty like India then India would have an easy supply of plutonium and... oops...
Anyway, it's been estimated that under extreme duress and given that Canada has the good metalurgists (for shaping the plutonium hemispheres), and the good electricians (for making accuratly timed charge triggers), and the good explosives-chemists (for the charges required to compress the hemisphers into critical mass), then theoretically, if pushed, could have a fat-boy style bomb in a week...
Of course, strategists would say that it would be wize and prudent for Canada to have all the parts for a plutonium bomb ready-made, sitting in secret warehouses, such that if it were necessary to build a bomb then it could be put together in a day, but seriously planet earth... Canada's just way too nice and all for the UN to ever think about doing something so sneaky as that.