Sthe judicial branch the least dangerous branch of the three (i. e. legislative, executive, and judicial)?

In Federalist No. 78, Hamilton said that the Judiciary branch of the proposed government would be the weakest of the three branches because it had "no influence over either the sword or the purse, ...It may truly be said to have neither FORCE nor WILL, but merely judgment." Federalist No. 78 quotes Montesquieu: "Of the three powers [...], the judiciary is next to nothing." There was little concern that the judiciary might be able to overpower the political branches; since Congress controlled the flow of money and the President the military, courts did not have nearly the same clout from a constitutional design standpoint. 

The answer is ethnic groups.