there is no bright line between republic and empire
the modern definition of Empire as per the British Empire, is to possess overseas sovereign territories
the American republic fits that definition, from Guam to Guantanamo
there is no bright line between republic and empire
UK has nukes.
Just take a 100 miles north of the border and you have Vancouver, Toronto, Montreal, basically everything we got except tundra, and some prime lumber, fossil fuel and minerals.
only American nukes, the British don't use their own nukes, they signed an agreement for America to provide their nukes