上句见：Day395
The Story of Philosophy《哲学的故事》第1章Plato第7节VI. The Psychological Solution第11段第6句：

Those who pass this first test will receive ten more years of education and training, in body and mind and character. And then they will face a second test, far severer than the first. Those who fail will become the auxiliaries, or executive aides and military officers of the state. Now it is just in these great eliminations that we shall need every resource of persuasion to get the eliminated to accept their fate with urbanity and peace. For what is to prevent that great unselected majority, in the first test, and that lesser but more vigorous and capable second group of Eliminees, from shouldering arms and smashing this Utopia of ours into a mouldering reminiscence? What is to prevent them from establishing there and then a world in which again mere number or mere force will rule, and the sickly comedy of a sham democracy will reënact itself da capo ad nauseam? Then religion and faith will be our only salvation: we shall tell these young people that the divisions into which they have fallen are God-decreed and irrevocable — not all their tears shall wipe out one word of it. We shall tell them the myth of the metals:
"Citizens, you are bothers, yet God has framed you differently. Some of you have the power of command; and these he has made of gold, wherefore they have the greatest honor; other of silver, to be auxiliaries; others again, who are to be husbandmen and craftsmen, he has made of brass and iron; and the species will generally be preserved in the children. But as you are of the same original family, a golden parent will sometimes have a silver son, or a silver parent a golden son. Are God proclaims … that if the son of a golden or a silver parent has an admixture of brass or iron, then nature requires a transposition of ranks; and the eye of the ruler must not be pitiful towards his child because he has to descend in the scale to become a husbandman or an artisan, just as there may be other sprung from the artisan class who are raised to honor, and become guardians and auxiliaries. For an oracle says that when a man of brass or iron guards the state, it will be destroyed"(415).
Perhaps with this "royal fable" we shall secure a fairly general consent to the furtherance of our plan.
浙江大学译本：又有什么东西能够阻止他们在彼时彼地建立一个仍旧只以数量或武力统治的世界，重演那令人作呕、虚伪病态的民主闹剧呢？

解析

1、What is to prevent them from establishing there and then a world in which again mere number or mere force will rule,
有什么可以阻止他们当场就建立一个世界，仍只靠数量或武力统治，
there and then: immediately in that moment and in that place当场就；当时当地
The engagement was concluded there and then.合同当场就谈妥了。《八十天环游地球》
2、and the sickly comedy of a sham democracy will reënact itself da capo ad nauseam?
永无止境地重演那虚伪民主的病态闹剧呢？
reënact: repeat the actions of (an event) 重演；再现；重现
He reënact the scenes from his TV series.
da capo: Italian = from the beginning 从头
ad nauseam: used to say that something happens or is done so many times or for such a long time that makes people annoyed, disgusted, etc.没完没了地；令人厌烦地
People in the tech industry or policy circles argue ad nauseam about whether the water temperature is changing and how much they think it's increasing.科技行业或政策圈的人们没完没了地讨论水温是否上升或上升了多少。

这句继续接上句，若这些淘汰者推翻了乌托邦，世界将重蹈覆辙，陷入民主闹剧的伦回。所以，选拔做好了，还要稳定它的成果，稳定中发挥其能力，不然就是功亏一篑。

有什么可以阻止他们当场就建立一个仍只靠数量或武力统治世界从而永无止境地重演那虚伪民主的病态闹剧呢？