Never in the Department’s 230-year history have we led a worldwide evacuation of such geographic scale and complexity,”Pompeo said.We have no higher duty to the american people than to pull this off.
第二句话Pompeo意思应该是比起完成撤侨大家没更要紧的任务，所以应该是not higher ,而不是no higher?
We have no higher duty to the american people than to pull this off.
本句的no higher... than...并非表示 既不...也不...。
这是比较级表示最高级意义。句子等于：
To pull it off is our highest duty to the American people.
To do it successfully is our highest duty to the American people.
做好撤侨这件事是大家对美国人民最崇高的职责。
pull off: informal:to do successfully
类似比较级表示最高级的例子：
How do you feel today?
I cant feel better. = I feel the best.