Are you having trouble saying that a functional, constitutional representative republic is the best form of government over any country, at any time?
Not at all, providing that the principles it is based upon are compatible with Catholic / Christian values. But not all republics are equal.
Are you having trouble saying that democracies are not objectively the same as republics and that a tyranny of a majority is less desirable than what Plato called philosopher kings, providing they espouse a wholly Christian philosophy?
Peace be with you