He sees the American nuclear umbrella as a real threat.

他认为美国的核保护伞是一个真正的威胁。

In his book, he confused the nucleon and nucleus, as he misunderstood the nuclear umbrella.

在他的书里，他混淆了核子与核心，正如他误解了核保护伞。

They also call for corresponding measures which may include things like a reduction of troop presence, American troops on the Korean Peninsula or getting rid of the nuclear umbrella that protects South Korea.

他们还呼吁采取相应措施，其中可能包括减少驻军，美国在朝鲜半岛的驻军，或者撤除保护韩国的核保护伞安全部队。

Stephen Schwartz, a nuclear weapons policy expert, said the key concern is the expansion of the nuclear umbrella to " include these new and not extreme possibilities, thus dramatically lowering the threshold for nuclear use."

核武器政策专家史蒂芬施瓦茨说，关键的问题是将核保护伞扩大到“覆盖这些新出现但并不极端的可能性，从而大大降低核用途的门槛。”