Per Alexander Hamilton;
In Federalist No. 62, Alexander Hamilton or James Madison explained that senators “ought” to be free “from the prepossessions and habits incident to foreign birth and education”, due to their “transactions with foreign nations”, so the nine-year citizenship requirement is a “prudent mediocrity” between totally excluding naturalized citizens and admitting them too quickly, “which might create a channel for foreign influence on the national councils”:
In Federalist 78
But it is easy to see, that it would require an uncommon portion of fortitude in the judges to do their duty as faithful guardians of the Constitution, where legislative invasions of it had been instigated by the major voice of the community.
Judges are the guardians of the Constitution. They do not create law!