Why is the difference in moon sightings (اختلاف المطالع) considered within the boundaries of countries drawn by colonialism, and not within each province or region, such that the people of an entire country fast if the crescent moon appears in the farthest border city, while the people of a neighboring city do not fast because it belongs to another country?

Scholars have agreed, both sensorially and intellectually, on the difference in the moon's rising places, but they have differed on two opinions regarding its consideration for the beginning and end of the Ramadan fast: Some considered it, holding that each land has its own sighting, while others did not consider it, deeming the sighting binding upon all lands. Both groups adduced evidence, and this issue is a matter of ijtihad (independent reasoning). The ruling of a Muslim ruler resolves disputes in matters of ijtihad. Thus, if the ruler deems it appropriate to consider the difference in moonrise or not, obedience to him becomes obligatory to preserve unity. Obedience is also due to whoever has taken control of a land and whose word has become effective in what is good.