..."Most tyrannical empire"? [...]
Maybe not
of all time, but as the most prolific warmonger of the few empires "
remaining on the planet" (to quote the portion of my statement that you neglected to quote), it could be argued that the US qualifies as "the most tyrannical empire remaining on the planet" ...by default. Moreover, taking into account the legislative assault on its own citizens -- from the so-called
Patriot Act to the NDAA -- it's clear that the
tryanny hasn't been reserved solely for foreign nationals.