Professor William McNeill comments [circa 1952]: “I feel that the Rome-Carthage relationship is a far more convincing parallel to contemporary conditions than the Rome-Parthia relationship. In the relations between Rome and Parthia mortal fear and the density of contact were, I believe, absent.” The present writer’s comment on this comment is that it was not too much to expect of American and Russian statesmanship in the sixth decade of the twentieth century of the Christian Era that it should stabilize the relation between the United States and the Soviet Union on a Romano-Parthian basis and save it from degenerating into a Romano-Carthaginian “irrepressible conflict”. [...]
Or a Romano-Sassanid, I suppose.
The phrase “irrepressible conflict” was used by William H Seward at Rochester, NY on October 25 1858.
Seward was a US senator who had served as Governor of New York and would serve as Secretary of State under Abraham Lincoln and Andrew Johnson. He argued that the political and economic systems of North and South were incompatible, and that, due to this “irrepressible conflict,” the “inevitable collision” of the two systems would eventually result in the nation becoming “either entirely a slave-holding nation or entirely a free-labor nation”. He hoped that this would be by the operation of natural forces over time, not by war.
Carthage was probably founded in the second half of the ninth century BC and was destroyed in the Third Punic War, 149-146 BC. Rome was founded in the middle of the eighth.
The Arsacid Parthian Empire lasted from 247 BC to AD 224. It replaced the Seleucid and was replaced, in the reign of Alexander Severus, by the Sassanid.
A Study of History, Vol IX, OUP, 1954 (footnote)