One difficulty of a deontological approach arises when the a…

One difficulty of a deontological approach arises when the approach conflicts with consequential reasoning. What happens when following a rule will have devastating consequences? For example, in WWII Germany, telling the truth to Nazis about Jews hiding in your attic would have had devastating consequences: the Jews would be taken and killed. According to Kant, what decision should you be willing to accept from anyone in the same position?