Because they had no influence over the budget and military.
In Hamilton's words that would be "no influence ever either the sword or the purse". He argued that because of this the judiciary would be the least threatening branch of the government and that it had to rely on both other branches to uphold its rulings and decisions. In Federalist No. 78 he also states what powers and responsibilities the judicial branch would have.
Yes, the supreme Court should have the ability to deem laws and executive actions unconstitutional, because that is it's job, it is too see if what one thing is is right or not
hope this helps
The purpose of passing the Neutrality Act of 1935 was because once the act was invoked, the US was in a better position to find a diplomatic solution to a conflict.
