question: Why were the clean slate decrees useful to the rulers of Sumer ?
answer: to prevent debts mounting to a degree that they threatened fighting force
turker_answer: The clean slate decrees were useful to the rulers of Sumer because they would prevent debts mounting to a degree that they threatened fighting force .
rule-based: The clean slate decrees useful to the rulers of Sumer were to prevent debts mounting to a degree that they threatened fighting force .