The US military uses the .mil domain, and Mali uses the .ml domain. People in the military/contractors keep typoing email addresses and sending them to the .ml domain instead of .mil.
The nuclear move would simply be for the military to disallow any emails to the .ml domain, and warn contractors about the issue so they can do the same. It’d block any legitimate emails to a .ml domain, but aside from diplomats there likely isn’t a huge need to email anyone at a .ml domain anyways. Those people who do need to do so could be selectively allowed to email .ml addresses.