"By defending" is correct and usable in written English
It is used to express the action of defending something in a specific manner. For example, "By defending his actions, he was able to prove his innocence."
By defending Ukraine, Mr Kolomoisky was also protecting his business empire.
By defending themselves, they are also defending the EU – rare in Europe nowadays.
By defending him, Corbyn was defending hate speech.
By defending me to him they were accepting his implied meaning: that witchery meant bitchery.
Carney responds by defending the Bank's actions.
Oz responded by defending his right to free speech.
Glenn defended his innocence by defending the water cure itself.
"They can't help but be distracted by defending past actions.
C.I.A. leaders prove their mettle inside the agency by defending career officers against congressional second-guessing.
We honor their lives by defending those rights — and the freedoms the terrorists attacked".
We honor their lives by defending those rights — and the freedoms that the terrorists attacked".
