「go so far as to do」で「～しさえする」という意味になります。
She went so far as to call me a liar.
彼女は私をうそつきとまで言った。
Even if you don't go so far as to grovel, how about a simple apology?
土下座をしないまでも、謝るぐらいはしたらどうだい。
He went so far as to say that it was worse than useless.
彼はそれが有害無益であるとまで言った。
I won't go so far as to say that she is a fool.
彼女がばかだとまでは言わないけれどね。
He went so far as to betray his own brothers.
彼は自分の兄弟さえも裏切った。
I wouldn't go as far as to say that.
そこまでは言えないが。
He went so far as to say that he knew absolutely nothing of it.
その事は全然知らないとまで彼は言った。