At a time when conspiracies run wild, this research stands as a rebuke to the know-nothings and zealots in dictatorships and democracies who behave as if the evidence for a claim is as nothing next to the identity of the person asserting it.

句中没有“嵌入式定语从句”，两个定语从句分别修饰不同的先行词（见蓝色部分）。

1.    when conspiracies run wild， 是 a time 的定语从句。

2. who behave as if the evidence for a claim is as nothing next to the identity of the person asserting it， 是the know-nothings and zealots 的定语从句。

3. the know-nothings and zealots （中心词：无知者和狂热者）in dictatorships and democracies（定语：在独裁国家和民主国家的）