I will defend to the death your right to do 的意思是“我会拼命维护你做某事的权利”。如：

1. While I disapprove of what you say, I would defend to the death your right to say it. 尽管我不赞成你所说的话，我还是要拼命维护你这样说的权利。

2. I will defend to the death your right to do what brings you genuine joy, provided it doesn’t violate the basic rights of others. 我会誓死捍卫你做能带给自己真正快乐的事的权利，前提是这不侵犯他人的基本权利。

3. I will defend to the death your right to do honest work that earns you a living, no matter how simple or unimportant others think it is. 我会誓死捍卫你通过诚实劳动谋生的权利，无论别人认为这份工作多么简单或无足轻重。

I will defend to the death your right to do ....的意思是：“我会拼命维护你做 ......的权利”。其中的 to the death 是介词短语，作状语。your right to do...是will defend的宾语。在宾语中，to do..是动词不定式短语，作定语。