Overseas European and US colonialism did not involve uniform national models exported to the periphery, contrary to an earlier historiography that sought to identify nationally-specific British, French, Spanish, or German approaches. Expansionist nation-states retained many of the features of traditional empires through the 19th century: the dual emphasis on stabilized peace and military strength, turbulent expansiveness, and a mixture of multiculturalism and universalizing ideology. Once the modern colonial states began operating, "native policy" quickly became their central activity. Modern colonial policies were organized according to a "rule of difference' between colonizers and colonized. One salient distinction between early-modern and modern colonialism concerns this rule of difference. Modern colonial states often had dualistic legal codes in which native legal disputes were processed by indigenous authorities – or according to a European rendering of indigenous law – while the colonizer was subject to a separate, supervenient framework of laws and rules.