▁do ▁hard ▁labor , ▁for ▁instance , ▁creating ▁ir rig ation ▁channels . ▁As ▁a ▁result ▁of ▁this , ▁war fare ▁between ▁rival ▁pol ities ▁was ▁very ▁pre val ent ▁during ▁this ▁period ▁in ▁order ▁to ▁gain ▁slave ▁labor ▁or ▁to ▁take ▁over ▁areas ▁that ▁had ▁already ▁been ▁ir rig ated . ▁Scott ▁goes ▁so ▁far ▁as ▁to ▁claim ▁that ▁" G ra ins ▁Make ▁States ." ▁ ▁The ▁introduction ▁of ▁a ▁st ap le ▁food ▁source ▁allowed ▁the ▁state ▁to ▁heavily ▁tax ▁the ▁people . ▁Gra ins , ▁especially ▁whe at , ▁became ▁the ▁best ▁way ▁to ▁tax ▁the ▁people . ▁Gra ins ▁like ▁whe at ▁or ▁rice ▁are ▁more ▁valuable ▁per ▁weight ▁than ▁other ▁sources ▁of ▁food , ▁and ▁much ▁easier ▁to ▁transport . ▁As ▁he ▁puts ▁it , ▁" The ▁key ▁to ▁the ▁ne x us ▁between ▁gra ins ▁and ▁states ▁lies , ▁I ▁believe , ▁in ▁the ▁fact ▁that ▁only ▁the ▁c ere al ▁gra ins ▁can ▁serve ▁as ▁a ▁basis ▁for ▁tax ation : ▁visible , ▁divis ible , ▁assess able , ▁stor able , ▁transport able , ▁and ▁' r ation able .' ▁Other ▁cro ps -- leg umes , ▁tub ers , ▁and ▁st arch ▁plans -- have ▁some ▁of ▁these ▁des irable ▁state - ada pt ed ▁qual ities , ▁but ▁none ▁has ▁all ▁of ▁these ▁advantages ." ▁M aking ▁people ▁pay ▁tax es ▁in ▁gra in ▁forced ▁people ▁to ▁shift ▁away ▁from ▁other ▁sources ▁of ▁food ▁that ▁they ▁may ▁have ▁preferred . ▁ ▁Chapter