Not to be dramatic, but wouldn't that level of destruction threaten all life on Earth? After the immediate destruction of the first county, extreme climate change would cause the same kind of problems as nuclear winter would, no?

Antimatter bombs are not a realistic technology. Aside from the unsolved technical issues - many, and fatal - no country has the GDP needed to make 1g of antimatter, which would make an explosion around 40kT.

We can't afford to blow up ourselves that way.

There are plenty of other ways we can afford, so antimatter isn't top of anyone's worries.

But they were wrong and we were right!