The correct answer is that the war would cost American lives.
Whenever the United States enters a war, there is also the risk of losing soldiers who are fighting over seas. This is general knowledge for most Americans, as they understand that the individuals who enroll in these services due run the risk of having to fight in potentially dangerous situations. This was no different during World War I, as this situation became a reality for thousands of soldiers.
From my research I could not find any such occurance, but the only similar situation was actually done by the Emperor Liu Bang to another neighboring country were he ordered his men to send letters attached to whics which led to the leader of the country to be killed as the subjects loss confidence in him.
They were able to grow their own food which was a plus for them since the rainfall helped increase their chances of getting food. Hopefully, this helps you. ^^