Sentence:  A nation such as Switzerland could be neutralized by agreement and could be relied upon to <WSD>protect</WSD> its neutrality ; more doubtful , but possible , ( with an assist from the North ) was the neutralization of the Latin American countries ; out of the question was the neutralization of Asia and Africa . 
Meaning of the word marked with <WSD> tags:  shield from danger, injury, destruction, or damage