Sometimes it’s hard to choose the right word in a language that isn’t your own; you aren’t quite sure of all the nuances that different options reflect. This is all the more so when a single word in your language can be rendered by two different words in your target language, as is the case with ‘defend’ and ‘protect’ in English, both of which often translate the Russian verb ‘защищать’.
In a court case, where a lawyer is providing representation to a party who is being sued or (in a criminal case) accused, then ‘defend’ is the correct verb. In the non-legal sense, it implies safeguarding someone or something from an attack.
‘Protect’ is a bit more general; it means to safeguard against or to preserve something from harm. However, it doesn’t necessarily imply an attack in the way that ‘defend’ does.
So you could say something along the lines of: ‘I took steps to protect my client by trying to reach a settlement with the tax authority, but when the tax office decided to litigate, I was forced to defend the company in court.’
In essence, if you use ‘defend’ each time the text speaks specifically about your role in court or what you do in response to some kind of attach, and ‘protect’ in more general contexts, you should be along the right lines.
