In order to have a theocratic republic, we would have to have a state religion.
We have pseudo-state-religions in Terran now. Sanguis Astroism and Triunism hold special legal privileges, and other religions have slightly restricted access.
Nobody in Terran is hyper-critical of Sanguis Astroism, or at least not public. I have nothing against SA. I don't want a modern Republic.
It's worth noting that ancient Greek republics had a state religion. I seem to recall Socrates drinking hemlock after being convicted of charges which included theological deviations of various kinds.
