英语翻译Just advanced by the Russians and later picked up made m

英语翻译
Just advanced by the Russians and later picked up made much of by certain American writers,was the claim that U2 pilots were worried that if the device had to be used the CIA had rigged it in such a way that it would explode premature
主要是中间那句 that if the device had to be used the CIA had rigged it in such a way that it would explode prematurely
最主要的是那个had to be used怎么理解
if 在这里如果是“如果”的意思.那么后面CIA发出的动作为什么不是would have done或者Would do