' s ▁God ▁ent itle ▁them ". ▁Some ▁early ▁American ▁law y ers ▁and ▁jud ges ▁perce ived ▁natural ▁law ▁as ▁too ▁ten uous , ▁am orph ous , ▁and ▁ev anes cent ▁a ▁legal ▁basis ▁for ▁ground ing ▁concrete ▁rights ▁and ▁government al ▁limitations . ▁Natural ▁law ▁did , ▁however , ▁serve ▁as ▁authority ▁for ▁legal ▁claims ▁and ▁rights ▁in ▁some ▁jud icial ▁dec isions , ▁legisl ative ▁acts , ▁and ▁legal ▁pron oun c ements . ▁Robert ▁Low ry ▁Cl inton ▁arg ues ▁that ▁the ▁U . S . ▁Constitution ▁rest s ▁on ▁a ▁common ▁law ▁foundation ▁and ▁the ▁common ▁law , ▁in ▁turn , ▁rest s ▁on ▁a ▁classical ▁natural ▁law ▁foundation . ▁ ▁European ▁liberal ▁natural ▁law ▁ ▁Liberal ▁natural ▁law ▁grew ▁out ▁of ▁the ▁medieval ▁Christian ▁natural ▁law ▁theories ▁and ▁out ▁of ▁Hob bes ' ▁revision ▁of ▁natural ▁law , ▁sometimes ▁in ▁an ▁une asy ▁balance ▁of ▁the ▁two . ▁ ▁Sir ▁Al ber ico ▁Gent ili ▁and ▁Hugo ▁Gro ti us ▁based ▁their ▁philosoph ies ▁of ▁international ▁law ▁on ▁natural ▁law . ▁In ▁particular , ▁his ▁writ ings ▁on ▁freedom ▁of ▁the ▁se as ▁and ▁just ▁war ▁theory ▁directly ▁appe aled ▁to ▁natural ▁law . ▁About ▁natural ▁law ▁itself , ▁he ▁wrote ▁that ▁" even ▁the ▁will ▁of ▁an ▁om n ip ot ent ▁being ▁cannot ▁change ▁or ▁ab rog ate " ▁natural ▁law , ▁which ▁" w ould ▁maintain ▁its ▁objective ▁valid ity ▁even ▁if ▁we ▁should ▁assume ▁the ▁impossible , ▁that ▁there ▁is ▁no ▁God