不错，是倒装语序。不过，网友写的句子不正确，应是：

Of nothing is that more true than foreign policy. （倒装语序）
That is more true of nothing than foreign policy.  （正常语序）

这是“否定词语”（作宾语、表语、状语时）放在句首引出的倒装。of nothing 是介词短语作表语，平常见到的多为状语。又如：

In no case should you give up. 你绝不能放弃。

On no condition should we tell her about it. 我们绝不能把此事告诉她。

On no accounts must this switch be touched. 这个开关是绝不能触摸的。

Under no circumstances should you lend him any money. 你无论如何都不该把钱借给他

No way will I go on working for that man. 我不再给那个人工作了。

By no means should you tell him about it. 你决不要告诉他这事。

At no time did he lose his self-control. 他始终没有失去控制力。

Not a single word did the boy write in his homework. 这男孩的家庭作业一个字也没写。（作宾语的 Not a single word 放在句首）