Rashi (on Bamidbar 22:5) invokes the famous explanation of Medrash Tanchuma, which asks why Hashem granted prophecy to Bilaam. Medrash Tanchuma answers that Hashem did so in order that the nations not claim that they were treated unfairly and argue that had they also been provided with prophets, they would have been more pious. To address this possible contention, Hashem granted prophecy to Bilaam - yet despite and as a result of this gift of prophecy to Bilaam, the nations actually sank lower into sin (i.e. the egregious acts at Ba'al Pe'or as precipitated by Midian, at the advice of Bilaam).

At first glance, Medrash Tanchuma does not seem to provide a balanced answer, for Bilaam was a most evil person, and he advised his followers to commit all types of misdeeds. Thus, it would appear that the nations did not really get a fair chance, for had they been provided with a prophet such as Moshe Rabbeinu, they would have been steered on a path of avodas Hashem. What is Medrash Tanchuma really telling us?

The answer is clear. Bilaam was a free-agent prophet. Unlike the Jewish nevi'im, he was not a leader. Moav and Midian did not seek Bilaam's objective prophetic advice, nor did they have any intent in becoming his disciples or appointing him as their leader in order to receive nevu'ah from Hashem so as to lead lives according to His Will. Rather, these nations sought to destroy B'nei Yisroel, and they exploited Bilaam's nevu'ah capabilities to this end. Bilaam, in his hatred for the Jews, was all too happy to cooperate for the right fee.

Thus, the nations were indeed given the opportunity for prophecy, but they voluntarily abused it in the extreme.

Medrash Tanchuma's position still seems to leave an open question, for why were the nations not given leaders such as Moshe? Surely such leaders would have inspired pureness of deed and attitude. Cannot the nations complain that they were unfairly granted leaders of lesser quality than those of B'nei Yisroel? Why did Medrash Tanchuma not consider this point?

The answer is that Jewish manhigim are not provided as a random or undeserved handout. Hashem provides inspiring and holy leaders due to His covenant with us, which was precipitated by a sincere and active commitment to Him on the part of the Avos and their close descendants. Thus, the system is merit-based, and B'nei Yisroel were indeed not given an "unfair" advantage.